@article{white_petrasova_petras_tateosian_vukomanovic_mitasova_meentemeyer_2023, title={An open-source platform for geospatial participatory modeling in the cloud}, volume={167}, ISSN={["1873-6726"]}, url={https://doi.org/10.1016/j.envsoft.2023.105767}, DOI={10.1016/j.envsoft.2023.105767}, abstractNote={Participatory modeling facilitates the co-production of knowledge and action by engaging stakeholders in research. However, the spatial dimensions of socio-environmental systems and decision-making are challenging to incorporate in participatory models, as developing interactive geospatial models requires specialized knowledge. Yet, many of society’s most pressing and complex socio-environmental problems require participatory modeling that is geospatial. Existing interactive online applications have broadened the audiences who can engage with geospatial models, but often do not provide a robust framework for interactive model development. Here, we develop an open-source platform, OpenPlains, to address barriers to participation in geospatial modeling by enabling researchers to develop interactive models that remove barriers to data aggregation and user engagement. OpenPlains consists of six new open-source libraries: OpenPlains, django-actina, grass-js-client, react-openplains, react-ol, and openplains-cli. We demonstrate OpenPlains through two web applications that work anywhere in the contiguous United States: a spatial–temporal watershed analysis application and an urban growth forecasting application.}, journal={ENVIRONMENTAL MODELLING & SOFTWARE}, publisher={Elsevier BV}, author={White, Corey T. and Petrasova, Anna and Petras, Vaclav and Tateosian, Laura G. and Vukomanovic, Jelena and Mitasova, Helena and Meentemeyer, Ross K.}, year={2023}, month={Sep} }
 @article{haedrich_petras_petrasova_blumentrath_mitasova_2023, title={Integrating GRASS GIS and Jupyter Notebooks to facilitate advanced geospatial modeling education}, volume={27}, url={https://doi.org/10.1111/tgis.13031}, DOI={10.1111/tgis.13031}, abstractNote={Abstract}, number={3}, journal={Transactions in GIS}, publisher={Wiley}, author={Haedrich, Caitlin and Petras, Vaclav and Petrasova, Anna and Blumentrath, Stefan and Mitasova, Helena}, year={2023}, month={May}, pages={686–702} }
 @article{howell_leon_everman_mitasova_nelson_richardson_2023, title={Performance of unoccupied aerial application systems for aquatic weed management: Two novel case studies}, volume={5}, ISSN={["1550-2740"]}, url={https://doi.org/10.1017/wet.2023.32}, DOI={10.1017/wet.2023.32}, abstractNote={Abstract}, journal={WEED TECHNOLOGY}, author={Howell, Andrew W. and Leon, Ramon G. and Everman, Wesley J. and Mitasova, Helena and Nelson, Stacy A. C. and Richardson, Robert J.}, year={2023}, month={May} }
 @article{petras_petrasova_mccarter_mitasova_meentemeyer_2023, title={Point Density Variations in Airborne Lidar Point Clouds}, volume={23}, ISSN={["1424-8220"]}, url={https://doi.org/10.3390/s23031593}, DOI={10.3390/s23031593}, abstractNote={In spite of increasing point density and accuracy, airborne lidar point clouds often exhibit point density variations. Some of these density variations indicate issues with point clouds, potentially leading to errors in derived products. To highlight these issues, we provide an overview of point density variations and show examples in six airborne lidar point cloud datasets that we used in our topographic and geospatial modeling research. Using the published literature, we identified sources of point density variations and issues indicated or caused by these variations. Lastly, we discuss the reduction in point density variations using decimations, homogenizations, and their applicability.}, number={3}, journal={SENSORS}, author={Petras, Vaclav and Petrasova, Anna and McCarter, James B. and Mitasova, Helena and Meentemeyer, Ross K.}, year={2023}, month={Feb} }
 @article{reckling_levine_nelson_mitasova_2023, title={Predicting residential septic system malfunctions for targeted drone inspections}, volume={30}, ISSN={["2352-9385"]}, url={https://doi.org/10.1016/j.rsase.2023.100936}, DOI={10.1016/j.rsase.2023.100936}, abstractNote={Septic system malfunctions can cause untreated sewage to pond in yards or contaminate drinking water wells leading to environmental and health problems. While most malfunction detections rely on reports by individuals, machine learning and remote sensing can be used to identify potentially failing systems. We propose a methodology that combines a machine learning technique implemented in Maxent with unmanned aerial system (UAS) mapping to create a priority queue for inspection and detecting malfunctions apparent in the collected imagery. We demonstrate the approach in Wake County, North Carolina, a County with 73,347 septic systems located within drinking water supply watersheds. The predictive modeling identified 102 systems with a 99.9% probability of failure. Four properties from the queue were mapped by UAS and the acquired imagery was visually analyzed in the visible spectrum for signs of malfunction. Our results suggest that the proposed approach can assist in the early identification of failing systems minimizing the environmental impacts and saving resource time and funds.}, journal={REMOTE SENSING APPLICATIONS-SOCIETY AND ENVIRONMENT}, author={Reckling, William and Levine, Jay and Nelson, Stacy A. C. and Mitasova, Helena}, year={2023}, month={Apr} }
 @article{sanchez_petrasova_skrip_collins_lawrimore_vogler_terando_vukomanovic_mitasova_meentemeyer_2023, title={Spatially interactive modeling of land change identifies location-specific adaptations most likely to lower future flood risk}, volume={13}, ISSN={["2045-2322"]}, url={http://dx.doi.org/10.1038/s41598-023-46195-9}, DOI={10.1038/s41598-023-46195-9}, abstractNote={Abstract}, number={1}, journal={SCIENTIFIC REPORTS}, publisher={Springer Science and Business Media LLC}, author={Sanchez, Georgina M. and Petrasova, Anna and Skrip, Megan M. and Collins, Elyssa L. and Lawrimore, Margaret A. and Vogler, John B. and Terando, Adam and Vukomanovic, Jelena and Mitasova, Helena and Meentemeyer, Ross K.}, year={2023}, month={Nov} }
 @article{mitas_badal_verhoeven_verstraten_graaf_mitasova_weijdema_klijs_2023, title={Tell Me Where to Go: An Experiment in Spreading Visitor Flows in The Netherlands}, url={https://doi.org/10.3390/ijerph20085441}, DOI={10.3390/ijerph20085441}, abstractNote={Cities attracting large numbers of tourists increasingly face crowding and public resistance to tourism growth. As a result, governments strive to spread tourists from the best-known attractions to less-visited locations to improve both residents’ and tourists’ quality of life. Evidence of success and best practices herein is largely anecdotal, and the effects on tourist experience are also unknown. Thus, we undertook a randomized 2 × 2 experiment in the province of Overijssel (The Netherlands), wherein tourists staying at vacation parks near small and mid-sized cities were exposed to information which emphasized attractions in either heavily visited or less-visited areas. Participants were also assigned to receive the information in either a passive or a conversational form. Location and daily emotion, as well as experience evaluation on the last day of the vacation, were recorded via mobile platforms. We found that tourists receiving information on attractions in less-visited areas engaged in significantly more movements around these attractions, and significantly less around heavily visited areas. The conversational form of information delivery was more positively evaluated than information delivered passively. Furthermore, vacation experience emotions and evaluations were largely unaffected. Thus, it is clearly possible to direct tourists to less-crowded locations without negatively affecting their vacation experiences.}, journal={International Journal of Environmental Research and Public Health}, author={Mitas, Ondrej and Badal, Rajneesh and Verhoeven, Maud and Verstraten, Koen and Graaf, Liselotte and Mitasova, Helena and Weijdema, Wendy and Klijs, Jeroen}, year={2023}, month={Apr} }
 @article{kotlarz_holcomb_pasha_reckling_kays_lai_daly_palani_bailey_guidry_et al._2023, title={Timing and Trends for Municipal Wastewater, Lab-Confirmed Case , and Syndromic Case Surveillance of COVID-19 in Raleigh, North Carolina}, volume={113}, ISSN={["1541-0048"]}, url={https://publons.com/wos-op/publon/54927766/}, DOI={10.2105/AJPH.2022.307108}, abstractNote={ Objectives. To compare 4 COVID-19 surveillance metrics in a major metropolitan area. }, number={1}, journal={AMERICAN JOURNAL OF PUBLIC HEALTH}, publisher={American Public Health Association}, author={Kotlarz, Nadine and Holcomb, David A. and Pasha, Tanvir and Reckling, Stacie and Kays, Judith and Lai, Yi-Chun and Daly, Sean and Palani, Sivaranjani and Bailey, Erika and Guidry, Virginia T. and et al.}, year={2023}, month={Jan}, pages={79–88} }
 @article{mitas_mitasova_millar_boode_neveu_hover_eijnden_bastiaansen_2022, title={More is Not Better: The Emotional Dynamics of an Excellent Experience}, volume={46}, ISSN={["1557-7554"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85091030484&partnerID=MN8TOARS}, DOI={10.1177/1096348020957075}, abstractNote={ Emotions embody the value in tourism experiences and drive essential outcomes such as intent to recommend. Current models do not explain how the ebb and flow of emotional arousal during an experience relate to outcomes, however. We analyzed 15 participants’ experiences at the Vincentre museum and guided village tour in Nuenen, the Netherlands. This Vincent van Gogh-themed experience led to a wide range of intent to recommend and emotional arousal, measured as continuous phasic skin conductance, across participants and exhibits. Mixed-effects analyses modeled emotional arousal as a function of proximity to exhibits and intent to recommend. Experiences with the best outcomes featured moments of both high and low emotional arousal, not one continuous “high,” with more emotion during the middle of the experience. Tourist experience models should account for a complex relationship between emotions experienced and outcomes such as intent to recommend. Simply put, more emotion is not always better. }, number={1}, journal={JOURNAL OF HOSPITALITY & TOURISM RESEARCH}, author={Mitas, Ondrej and Mitasova, Helena and Millar, Garrett and Boode, Wilco and Neveu, Vincent and Hover, Moniek and Eijnden, Frank and Bastiaansen, Marcel}, year={2022}, month={Jan}, pages={78–99} }
 @article{collins_sanchez_terando_stillwell_mitasova_sebastian_meentemeyer_2022, title={Predicting flood damage probability across the conterminous United States}, volume={17}, ISSN={["1748-9326"]}, url={https://doi.org/10.1088/1748-9326/ac4f0f}, DOI={10.1088/1748-9326/ac4f0f}, abstractNote={Abstract}, number={3}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Collins, Elyssa L. and Sanchez, Georgina M. and Terando, Adam and Stillwell, Charles C. and Mitasova, Helena and Sebastian, Antonia and Meentemeyer, Ross K.}, year={2022}, month={Mar} }
 @article{white_reckling_petrasova_meentemeyer_mitasova_2022, title={Rapid-DEM: Rapid Topographic Updates through Satellite Change Detection and UAS Data Fusion}, volume={14}, ISSN={["2072-4292"]}, url={https://www.mdpi.com/2072-4292/14/7/1718}, DOI={10.3390/rs14071718}, abstractNote={As rapid urbanization occurs in cities worldwide, the importance of maintaining updated digital elevation models (DEM) will continue to increase. However, due to the cost of generating high-resolution DEM over large spatial extents, the temporal resolution of DEMs is coarse in many regions. Low-cost unmanned aerial vehicles (UAS) and DEM data fusion provide a partial solution to improving the temporal resolution of DEM but do not identify which areas of a DEM require updates. We present Rapid-DEM, a framework that identifies and prioritizes locations with a high likelihood of an urban topographic change to target UAS data acquisition and fusion to provide up-to-date DEM. The framework uses PlanetScope 3 m satellite imagery, Google Earth Engine, and OpenStreetMap for land cover classification. GRASS GIS generates a contextualized priority queue from the land cover data and outputs polygons for UAS flight planning. Low-cost UAS fly the identified areas, and WebODM generates a DEM from the UAS survey data. The UAS data is fused with an existing DEM and uploaded to a public data repository. To demonstrate Rapid-DEM a case study in the Walnut Creek Watershed in Wake County, North Carolina is presented. Two land cover classification models were generated using random forests with an overall accuracy of 89% (kappa 0.86) and 91% (kappa 0.88). The priority queue identified 109 priority locations representing 1.5% area of the watershed. Large forest clearings were the highest priority locations, followed by newly constructed buildings. The highest priority site was a 0.5 km2 forest clearing that was mapped with UAS, generating a 15 cm DEM. The UAS DEM was resampled to 3 m resolution and fused with USGS NED 1/9 arc-second DEM data. Surface water flow was simulated over the original and updated DEM to illustrate the impact of the topographic change on flow patterns and highlight the importance of timely DEM updates.}, number={7}, journal={REMOTE SENSING}, publisher={MDPI AG}, author={White, Corey T. and Reckling, William and Petrasova, Anna and Meentemeyer, Ross K. and Mitasova, Helena}, year={2022}, month={Apr} }
 @article{burgener_hyland_griffith_mitasova_zanno_gates_2021, title={An extreme climate gradient-induced ecological regionalization in the Upper Cretaceous Western Interior Basin of North America}, volume={133}, ISSN={["1943-2674"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85111073513&partnerID=MN8TOARS}, DOI={10.1130/B35904.1}, abstractNote={Abstract}, number={9-10}, journal={GEOLOGICAL SOCIETY OF AMERICA BULLETIN}, author={Burgener, Landon and Hyland, Ethan and Griffith, Emily and Mitasova, Helena and Zanno, Lindsay E. and Gates, Terry A.}, year={2021}, pages={2125–2136} }
 @article{rucker_tull_dietrich_langan_mitasova_blanton_fleming_luettich_2021, title={Downscaling of real-time coastal flooding predictions for decision support}, volume={107}, ISSN={["1573-0840"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85101369844&partnerID=MN8TOARS}, DOI={10.1007/s11069-021-04634-8}, abstractNote={During coastal storms, forecasters and researchers use numerical models to predict the magnitude and extent of coastal flooding. These models must represent the large regions that may be affected by a storm, and thus, they can be computationally costly and may not use the highest geospatial resolution. However, predicted flood extents can be downscaled (by increasing resolution) as a post-processing step. Existing downscaling methods use either a static extrapolation of the flooding as a flat surface, or rely on subsequent simulations with nested, full-physics models at higher resolution. This research explores a middle way, in which the downscaling includes simplified physics to improve accuracy. Using results from a state-of-the-art model, we downscale its flood predictions with three methods: (1) static, in which the water surface elevations are extrapolated horizontally until they intersect the ground surface; (2) slopes, in which the gradient of the water surface is used; and (3) head loss, which accounts for energy losses due to land cover characteristics. The downscaling methods are then evaluated for forecasts and hindcasts of Hurricane Florence (2018), which caused widespread flooding in North Carolina. The static and slopes methods tend to over-estimate the flood extents. However, the head loss method generates a downscaled flooding extent that is a close match to the predictions from a higher-resolution, full-physics model. These results are encouraging for the use of these downscaling methods to support decision-making during coastal storms.}, number={2}, journal={NATURAL HAZARDS}, publisher={Springer Science and Business Media LLC}, author={Rucker, C. A. and Tull, N. and Dietrich, J. C. and Langan, T. E. and Mitasova, H. and Blanton, B. O. and Fleming, J. G. and Luettich, R. A., Jr.}, year={2021}, month={Jun}, pages={1341–1369} }
 @article{reckling_mitasova_wegmann_kauffman_reid_2021, title={Efficient Drone-Based Rare Plant Monitoring Using a Species Distribution Model and AI-Based Object Detection}, volume={5}, ISSN={["2504-446X"]}, url={https://www.mdpi.com/2504-446X/5/4/110}, DOI={10.3390/drones5040110}, abstractNote={Monitoring rare plant species is used to confirm presence, assess health, and verify population trends. Unmanned aerial systems (UAS) are ideal tools for monitoring rare plants because they can efficiently collect data without impacting the plant or endangering personnel. However, UAS flight planning can be subjective, resulting in ineffective use of flight time and overcollection of imagery. This study used a Maxent machine-learning predictive model to create targeted flight areas to monitor Geum radiatum, an endangered plant endemic to the Blue Ridge Mountains in North Carolina. The Maxent model was developed with ten environmental layers as predictors and known plant locations as training data. UAS flight areas were derived from the resulting probability raster as isolines delineated from a probability threshold based on flight parameters. Visual analysis of UAS imagery verified the locations of 33 known plants and discovered four previously undocumented occurrences. Semi-automated detection of plant species was explored using a neural network object detector. Although the approach was successful in detecting plants in on-ground images, no plants were identified in the UAS aerial imagery, indicating that further improvements are needed in both data acquisition and computer vision techniques. Despite this limitation, the presented research provides a data-driven approach to plan targeted UAS flight areas from predictive modeling, improving UAS data collection for rare plant monitoring.}, number={4}, journal={DRONES}, publisher={MDPI AG}, author={Reckling, William and Mitasova, Helena and Wegmann, Karl and Kauffman, Gary and Reid, Rebekah}, year={2021}, month={Dec} }
 @article{gaydos_jones_jones_millar_petras_petrasova_mitasova_meentemeyer_2021, title={Evaluating online and tangible interfaces for engaging stakeholders in forecasting and control of biological invasions}, volume={9}, ISSN={["1939-5582"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85115251448&partnerID=MN8TOARS}, DOI={10.1002/eap.2446}, abstractNote={Abstract}, number={8}, journal={ECOLOGICAL APPLICATIONS}, publisher={Wiley}, author={Gaydos, Devon A. and Jones, Chris M. and Jones, Shannon K. and Millar, Garrett C. and Petras, Vaclav and Petrasova, Anna and Mitasova, Helena and Meentemeyer, Ross K.}, year={2021}, month={Sep} }
 @article{petras_mitasova_petrasova_2021, title={Open Source Software Development}, url={https://doi.org/10.22224/gistbok/2021.2.4}, DOI={10.22224/gistbok/2021.2.4}, journal={Geographic Information Science & Technology Body of Knowledge}, author={Petras, Vaclav and Mitasova, Helena and Petrasova, Anna}, year={2021}, month={Apr} }
 @article{millar_mitas_boode_hoeke_kruijf_petrasova_mitasova_2021, title={Space-time analytics of human physiology for urban planning}, volume={85}, ISBN={1873-7587}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85092914107&partnerID=MN8TOARS}, DOI={10.1016/j.compenvurbsys.2020.101554}, abstractNote={Recent advancements in mobile sensing and wearable technologies create new opportunities to improve our understanding of how people experience their environment. This understanding can inform urban design decisions. Currently, an important urban design issue is the adaptation of infrastructure to increasing cycle and e-bike use. Using data collected from 12 cyclists on a cycle highway between two municipalities in The Netherlands, we coupled location and wearable emotion data at a high spatiotemporal resolution to model and examine relationships between cyclists' emotional arousal (operationalized as skin conductance responses) and visual stimuli from the environment (operationalized as extent of visible land cover type). We specifically took a within-participants multilevel modeling approach to determine relationships between different types of viewable land cover area and emotional arousal, while controlling for speed, direction, distance to roads, and directional change. Surprisingly, our model suggests ride segments with views of larger natural, recreational, agricultural, and forested areas were more emotionally arousing for participants. Conversely, segments with views of larger developed areas were less arousing. The presented methodological framework, spatial-emotional analyses, and findings from multilevel modeling provide new opportunities for spatial, data-driven approaches to portable sensing and urban planning research. Furthermore, our findings have implications for design of infrastructure to optimize cycling experiences.}, journal={COMPUTERS ENVIRONMENT AND URBAN SYSTEMS}, author={Millar, Garrett C. and Mitas, Ondrej and Boode, Wilco and Hoeke, Lisette and Kruijf, Joost and Petrasova, Anna and Mitasova, Helena}, year={2021}, month={Jan} }
 @article{white_mitasova_bendor_foy_pala_vukomanovic_meentemeyer_2021, title={Spatially Explicit Fuzzy Cognitive Mapping for Participatory Modeling of Stormwater Management}, volume={10}, ISSN={["2073-445X"]}, url={https://doi.org/10.3390/land10111114}, DOI={10.3390/land10111114}, abstractNote={Addressing “wicked” problems like urban stormwater management necessitates building shared understanding among diverse stakeholders with the influence to enact solutions cooperatively. Fuzzy cognitive maps (FCMs) are participatory modeling tools that enable diverse stakeholders to articulate the components of a socio-environmental system (SES) and describe their interactions. However, the spatial scale of an FCM is rarely explicitly considered, despite the influence of spatial scale on SES. We developed a technique to couple FCMs with spatially explicit survey data to connect stakeholder conceptualization of urban stormwater management at a regional scale with specific stormwater problems they identified. We used geospatial data and flooding simulation models to quantitatively evaluate stakeholders’ descriptions of location-specific problems. We found that stakeholders used a wide variety of language to describe variables in their FCMs and that government and academic stakeholders used significantly different suites of variables. We also found that regional FCM did not downscale well to concerns at finer spatial scales; variables and causal relationships important at location-specific scales were often different or missing from the regional FCM. This study demonstrates the spatial framing of stormwater problems influences the perceived range of possible problems, barriers, and solutions through spatial cognitive filtering of the system’s boundaries.}, number={11}, journal={LAND}, publisher={MDPI AG}, author={White, Corey T. and Mitasova, Helena and BenDor, Todd K. and Foy, Kevin and Pala, Okan and Vukomanovic, Jelena and Meentemeyer, Ross K.}, year={2021}, month={Nov} }
 @inproceedings{white_petrasova_reckling_mitasova_2020, title={AUTOMATED LAND COVER CHANGE DETECTION through RAPID UAS UPDATES of DIGITAL SURFACE MODELS}, volume={42}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85081623143&partnerID=MN8TOARS}, DOI={10.5194/isprs-archives-XLII-3-W11-155-2020}, abstractNote={Abstract. Up to date geospatial data provide the foundation for the development of smart and connected communities. While high-resolution 2D imagery is becoming widely available at less than monthly intervals and several infrastructure layers (e.g., roads, building footprints) are updated on a continuous basis, digital surface models (DSM) are generated less frequently and become quickly obsolete in rapidly developing regions. We present a methodology for continuous and efficient updates of DSM based on automated change detection from high-resolution satellite imagery that is used to develop UAS deployment plan, data acquisition, and DSM generation for targeted areas. The resulting UAS-derived DSM is then seamlessly fused with existing (usually lidar-based) DSM. We demonstrate our methodology in a rapidly developing watershed in the Triangle Region, North Carolina. The change detection maps were created using pixel-based classification methods on monthly composite data generated from PlanetScope satellites (3m resolution) as input for UAS flight planning, data acquisition, and processing. In future work a GRASS GIS script using a moving window resampling process will create flight areas to resample the change detection output into 10 acres flight areas for the UAS flight planning software, and a plugin for WebODM will be developed using GRASS GIS to enable seamless updates to centralized repositories of DSM.
                    }, number={3/W11}, booktitle={International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives}, author={White, C.T. and Petrasova, A. and Reckling, W. and Mitasova, H.}, year={2020}, pages={155–159} }
 @article{smart_taillie_poulter_vukomanovic_singh_swenson_mitasova_smith_meentemeyer_2020, title={Aboveground carbon loss associated with the spread of ghost forests as sea levels rise}, volume={15}, ISSN={["1748-9326"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85092484857&partnerID=MN8TOARS}, DOI={10.1088/1748-9326/aba136}, abstractNote={Abstract}, number={10}, journal={ENVIRONMENTAL RESEARCH LETTERS}, author={Smart, Lindsey S. and Taillie, Paul J. and Poulter, Benjamin and Vukomanovic, Jelena and Singh, Kunwar K. and Swenson, Jennifer J. and Mitasova, Helena and Smith, Jordan W. and Meentemeyer, Ross K.}, year={2020}, month={Oct} }
 @article{petrasova_gaydos_petras_jones_mitasova_meentemeyer_2020, title={Geospatial simulation steering for adaptive management}, volume={133}, url={https://doi.org/10.1016/j.envsoft.2020.104801}, DOI={10.1016/j.envsoft.2020.104801}, abstractNote={Spatio-temporal simulations are becoming essential tools for decision makers when forecasting future conditions and evaluating effectiveness of alternative decision scenarios. However, lack of interactive steering capabilities limits the value of advanced stochastic simulations for research and practice. To address this gap we identified conceptual challenges associated with steering stochastic, spatio-temporal simulations and developed solutions that better represent the realities of decision-making by allowing both reactive and proactive, spatially-explicit interventions. We present our approach, in a participatory modeling case study engaging stakeholders in developing strategies to contain the spread of a tree disease in Oregon, USA. Using intuitive interfaces, implemented through web-based and tangible platforms, stakeholders explored management options as the simulation progressed. Spatio-temporal steering allowed them to combine currently used management practices into novel adaptive management strategies, which were previously difficult to test and assess, demonstrating the utility of interactive simulations for decision-making.}, journal={Environmental Modelling & Software}, publisher={Elsevier BV}, author={Petrasova, Anna and Gaydos, Devon A. and Petras, Vaclav and Jones, Chris M. and Mitasova, Helena and Meentemeyer, Ross K.}, year={2020}, month={Nov}, pages={104801} }
 @article{tabrizian_petrasova_baran_vukomanovic_mitasova_meentemeyer_2020, title={High Resolution Viewscape Modeling Evaluated Through Immersive Virtual Environments}, volume={9}, url={https://doi.org/10.3390/ijgi9070445}, DOI={10.3390/ijgi9070445}, abstractNote={Visual characteristics of urban environments influence human perception and behavior, including choices for living, recreation and modes of transportation. Although geospatial visualizations hold great potential to better inform urban planning and design, computational methods are lacking to realistically measure and model urban and parkland viewscapes at sufficiently fine-scale resolution. In this study, we develop and evaluate an integrative approach to measuring and modeling fine-scale viewscape characteristics of a mixed-use urban environment, a city park. Our viewscape approach improves the integration of geospatial and perception elicitation techniques by combining high-resolution lidar-based digital surface models, visual obstruction, and photorealistic immersive virtual environments (IVEs). We assessed the realism of our viewscape models by comparing metrics of viewscape composition and configuration to human subject evaluations of IVEs across multiple landscape settings. We found strongly significant correlations between viewscape metrics and participants’ perceptions of viewscape openness and naturalness, and moderately strong correlations with landscape complexity. These results suggest that lidar-enhanced viewscape models can adequately represent visual characteristics of fine-scale urban environments. Findings also indicate the existence of relationships between human perception and landscape pattern. Our approach allows urban planners and designers to model and virtually evaluate high-resolution viewscapes of urban parks and natural landscapes with fine-scale details never before demonstrated.}, number={7}, journal={ISPRS International Journal of Geo-Information}, publisher={MDPI AG}, author={Tabrizian, Payam and Petrasova, Anna and Baran, Perver and Vukomanovic, Jelena and Mitasova, Helena and Meentemeyer, Ross}, year={2020}, month={Jul}, pages={445} }
 @article{mobasheri_mitasova_neteler_singleton_ledoux_brovelli_2020, title={Highlighting recent trends in open source geospatial science and software}, volume={24}, ISSN={["1467-9671"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85092776687&partnerID=MN8TOARS}, DOI={10.1111/tgis.12703}, abstractNote={Abstract}, number={5}, journal={TRANSACTIONS IN GIS}, author={Mobasheri, Amin and Mitasova, Helena and Neteler, Markus and Singleton, Alexander and Ledoux, Hugo and Brovelli, Maria Antonia}, year={2020}, month={Oct}, pages={1141–1146} }
 @article{montgomery_henry_vann_whipker_huseth_mitasova_2020, title={Measures of Canopy Structure from Low-Cost UAS for Monitoring Crop Nutrient Status}, volume={4}, ISSN={2504-446X}, url={http://dx.doi.org/10.3390/drones4030036}, DOI={10.3390/drones4030036}, abstractNote={Deriving crop information from remotely sensed data is an important strategy for precision agriculture. Small unmanned aerial systems (UAS) have emerged in recent years as a versatile remote sensing tool that can provide precisely-timed, fine-grained data for informing management responses to intra-field crop variability (e.g., nutrient status and pest damage). UAS sensors with high spectral resolution used to compute informative vegetation indices, however, are practically limited by high cost and data dimensionality. This research extends spectral analysis for remote crop monitoring to investigate the relationship between crop health and 3D canopy structure using low-cost UAS equipped with consumer-grade RGB cameras. We used flue-cured tobacco as a case study due to its known sensitivity to fertility variation and nutrient-specific symptomology. Fertilizer treatments were applied to induce plant health variability in a 0.5 ha field of flue-cured tobacco. Multi-view stereo images from three UAS surveys collected during crop development were processed into orthoimages used to compute a visible band spectral index and photogrammetric point clouds using Structure from Motion (SfM). Plant structural metrics were then computed from detailed high resolution canopy surface models (0.05 m resolution) interpolated from the photogrammetric point clouds. The UAS surveys were complimented by nutrient status measurements obtained from plant tissues. The relationships between foliar nitrogen (N), phosphorus (P), potassium (K), and boron (B) concentrations and the UAS-derived metrics were assessed using multiple linear regression. Symptoms of N and K deficiencies were well captured and differentiated by the structural metrics. The strongest relationship observed was between canopy shape and N foliar concentration (adj. r2 = 0.59, increasing to adj. r2 = 0.81 when combined with the spectral index). B foliar concentration was consistently better predicted by canopy structure with a maximum adj. r2 = 0.41 observed at the latest growth stage surveyed. Overall, combining information about canopy structure and spectral reflectance increased model fit for all measured nutrients compared to spectral alone. These results suggest that an important relationship exists between relative canopy shape and crop health that can be leveraged to improve the usefulness of low cost UAS for precision agriculture.}, number={3}, journal={Drones}, publisher={MDPI AG}, author={Montgomery, Kellyn and Henry, Josh and Vann, Matthew and Whipker, Brian E. and Huseth, Anders and Mitasova, Helena}, year={2020}, month={Jul}, pages={36} }
 @article{tabrizian_baran_van berkel_mitasova_meentemeyer_2020, title={Modeling restorative potential of urban environments by coupling viewscape analysis of lidar data with experiments in immersive virtual environments}, volume={195}, ISSN={["1872-6062"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85076054188&partnerID=MN8TOARS}, DOI={10.1016/j.landurbplan.2019.103704}, abstractNote={• We propose an approach for modeling experiential qualities of urban landscape. • We use lidar data to generate detailed model of landscape structure and patterns. • We combine GIS analysis of viewscapes with survey of immersive virtual environment. • We identify spatial metrics that predict urban landscape’s restorative potential (RP). • We develop a predictive map of RP that can support decision-making and urban design.}, journal={LANDSCAPE AND URBAN PLANNING}, author={Tabrizian, Payam and Baran, Perver K. and Van Berkel, Derek and Mitasova, Helena and Meentemeyer, Ross}, year={2020}, month={Mar} }
 @article{coetzee_ivánová_mitasova_brovelli_2020, title={Open Geospatial Software and Data: A Review of the Current State and A Perspective into the Future}, volume={9}, url={https://doi.org/10.3390/ijgi9020090}, DOI={10.3390/ijgi9020090}, abstractNote={All over the world, organizations are increasingly considering the adoption of open source software and open data. In the geospatial domain, this is no different, and the last few decades have seen significant advances in this regard. We review the current state of open source geospatial software, focusing on the Open Source Geospatial Foundation (OSGeo) software ecosystem and its communities, as well as three kinds of open geospatial data (collaboratively contributed, authoritative and scientific). The current state confirms that openness has changed the way in which geospatial data are collected, processed, analyzed, and visualized. A perspective on future developments, informed by responses from professionals in key organizations in the global geospatial community, suggests that open source geospatial software and open geospatial data are likely to have an even more profound impact in the future.}, number={2}, journal={ISPRS International Journal of Geo-Information}, publisher={MDPI AG}, author={Coetzee, Serena and Ivánová, Ivana and Mitasova, Helena and Brovelli, Maria}, year={2020}, month={Feb}, pages={90} }
 @article{starek_chu_mitasova_harmon_2020, title={Viewshed simulation and optimization for digital terrain modelling with terrestrial laser scanning}, volume={41}, ISSN={["1366-5901"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85087281550&partnerID=MN8TOARS}, DOI={10.1080/01431161.2020.1752952}, abstractNote={ABSTRACT The main objective of this study is the development of a simulation and optimization method for wide-area terrain mapping with terrestrial laser scanning (TLS). The problem can be stated as follows: given a prior digital surface model (DSM) of a region of interest (e.g. from airborne lidar or structure-from-motion photogrammetry), determine the minimum number of scan locations required to seamlessly scan the terrain in the region for a given scanner range and angular field-of-view (FOV). An optimization method for measurement setup is developed using multiple viewshed analysis and simulated annealing (SA) constrained by the system performance characteristics and survey specifications. The method is evaluated at a sediment and erosion control facility with hilly terrain by comparing random scan locations versus optimized three to six scan locations. Statistical results illustrate that average visibility for random sampling increases gradually with scan locations. However, random sampling clearly underperforms in terms of scan visibility relative to five or six optimized scan locations with an average visibility of 100%. Similar patterns in optimized scan locations demonstrate that certain terrain morphometry at the study site is an essential factor for TLS survey design. Finally, an optimized solution is compared to a brute-force manual solution for determining four scan locations for conducting surveys at the study site. Results show the effectiveness of the optimization method for selecting combinations of scan locations that enable more efficient TLS survey coverage over a wider terrain area compared to manual selection. Furthermore, results demonstrate the adaptability of the method to take into consideration different scan parameters and survey conditions, such as pre-determined scan locations that may be required (e.g. a survey control monument).}, number={16}, journal={INTERNATIONAL JOURNAL OF REMOTE SENSING}, author={Starek, Michael J. and Chu, Tianxing and Mitasova, Helena and Harmon, Russell S.}, year={2020}, month={Aug}, pages={6409–6426} }
 @article{berkel_shashidharan_mordecai_vatsavai_petrasova_petras_mitasova_vogler_meentemeyer_2019, title={Projecting Urbanization and Landscape Change at Large Scale Using the FUTURES Model}, volume={8}, url={https://www.mdpi.com/2073-445X/8/10/144}, DOI={10.3390/land8100144}, abstractNote={Increasing population and rural to urban migration are accelerating urbanization globally, permanently transforming natural systems over large extents. Modelling landscape change over large regions, however, presents particular challenges due to local-scale variations in social and environmental factors that drive land change. We simulated urban development across the South Atlantic States (SAS), a region experiencing rapid population growth and urbanization, using FUTURES—an open source land change model that uses demand for development, local development suitability factors, and a stochastic patch growing algorithm for projecting alternative futures of urban form and landscape change. New advances to the FUTURES modelling framework allow for high resolution projections over large spatial extents by leveraging parallel computing. We simulated the adoption of different urban growth strategies that encourage settlement densification in the SAS as alternatives to the region’s increasing sprawl. Evaluation of projected patterns indicate a 15% increase in urban lands by 2050 given a status quo development scenario compared to a 14.8% increase for the Infill strategy. Status quo development resulted in a 3.72% loss of total forests, 2.97% loss of highly suitable agricultural land, and 3.69% loss of ecologically significant lands. An alternative Infill scenario resulted in similar losses of total forest (3.62%) and ecologically significant lands (3.63%) yet consumed less agricultural lands (1.23% loss). Moreover, infill development patterns differed qualitatively from the status quo and resulted in less fragmentation of the landscape.}, number={10}, journal={Land}, publisher={MDPI AG}, author={Berkel, Derek Van and Shashidharan, Ashwin and Mordecai, Rua S. and Vatsavai, Raju and Petrasova, Anna and Petras, Vaclav and Mitasova, Helena and Vogler, John B. and Meentemeyer, Ross K.}, year={2019}, month={Sep}, pages={144} }
 @article{petrasova_hipp_mitasova_2019, title={Visualization of Pedestrian Density Dynamics Using Data Extracted from Public Webcams}, volume={8}, url={https://doi.org/10.3390/ijgi8120559}, DOI={10.3390/ijgi8120559}, abstractNote={Accurate information on the number and distribution of pedestrians in space and time helps urban planners maintain current city infrastructure and design better public spaces for local residents and visitors. Previous studies have demonstrated that using webcams together with crowdsourcing platforms to locate pedestrians in the captured images is a promising technique for analyzing pedestrian activity. However, it is challenging to efficiently transform the time series of pedestrian locations in the images to information suitable for geospatial analytics, as well as visualize data in a meaningful way to inform urban design or decision making. In this study, we propose to use a space-time cube (STC) representation of pedestrian data to analyze the spatio-temporal patterns of pedestrians in public spaces. We take advantage of AMOS (The Archive of Many Outdoor Scenes), a large database of images captured by thousands of publicly available, outdoor webcams. We developed a method to obtain georeferenced spatio-temporal data from webcams and to transform them into high-resolution continuous representation of pedestrian densities by combining bivariate kernel density estimation with trivariate, spatio-temporal spline interpolation. We demonstrate our method on two case studies analyzing pedestrian activity of two city plazas. The first case study explores daily and weekly spatio-temporal patterns of pedestrian activity while the second one highlights the differences in pattern before and after plaza’s redevelopment. While STC has already been used to visualize urban dynamics, this is the first study analyzing the evolution of pedestrian density based on crowdsourced time series of pedestrian occurrences captured by webcam images.}, number={12}, journal={ISPRS International Journal of Geo-Information}, publisher={MDPI AG}, author={Petrasova, Anna and Hipp, J. Aaron and Mitasova, Helena}, year={2019}, month={Dec}, pages={559} }
 @article{harmon_mitasova_petrasova_petras_2019, title={r.sim.terrain 1.0: a landscape evolution model with dynamic hydrology}, volume={12}, ISSN={["1991-9603"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85068763744&partnerID=MN8TOARS}, DOI={10.5194/gmd-12-2837-2019}, abstractNote={Abstract. While there are numerical landscape evolution models that simulate how steady-state flows of water and sediment reshape topography over long periods of time, r.sim.terrain is the first to simulate short-term topographic change for both steady-state and dynamic flow regimes across a range of spatial scales. This free and open-source Geographic Information Systems (GIS)-based topographic evolution model uses empirical models for soil erosion and a physics-based model for shallow overland water flow and soil erosion to compute short-term topographic change. This model uses either a steady-state or unsteady representation of overland flow to simulate how overland sediment mass flows reshape topography for a range of hydrologic soil erosion regimes based on topographic, land cover, soil, and rainfall parameters. As demonstrated by a case study for the Patterson Branch subwatershed on the Fort Bragg military installation in North Carolina, r.sim.terrain simulates the development of fine-scale morphological features including ephemeral gullies, rills, and hillslopes. Applications include land management, erosion control, landscape planning, and landscape restoration.}, number={7}, journal={GEOSCIENTIFIC MODEL DEVELOPMENT}, author={Harmon, Brendan Alexander and Mitasova, Helena and Petrasova, Anna and Petras, Vaclav}, year={2019}, month={Jul}, pages={2837–2854} }
 @article{paris_mitasova_2018, title={Geospatial contrasts between natural and human-altered barrier island systems: Core Banks and Ocracoke Island, North Carolina, USA}, volume={22}, ISSN={["1874-7841"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85042115027&partnerID=MN8TOARS}, DOI={10.1007/s11852-018-0601-5}, number={4}, journal={JOURNAL OF COASTAL CONSERVATION}, author={Paris, Paul J. and Mitasova, Helena}, year={2018}, month={Aug}, pages={679–694} }
 @article{velasquez montoya_sciaudone_mitasova_overton_2018, title={Observation and modeling of the evolution of an ephemeral storm-induced inlet: Pea Island Breach, North Carolina, USA}, volume={156}, ISSN={0278-4343}, url={http://dx.doi.org/10.1016/j.csr.2018.02.002}, DOI={10.1016/j.csr.2018.02.002}, abstractNote={The Outer Banks of North Carolina is a wave-dominated barrier island system that has experienced the opening and closure of numerous inlets in the last four centuries. The most recent of those inlets formed after the breaching of Pea Island during Hurricane Irene in 2011. The Pea Island Breach experienced a rapid evolution including episodic curvature of the main channel, rotation of the ebb channel, shoaling, widening by Hurricane Sandy in 2012, and finally closing before the summer of 2013. Studying the life cycle of Pea Island Breach contributes to understanding the behavior of ephemeral inlets in breaching-prone regions. This topic has gained relevance due to rising sea levels, a phenomenon that increases the chances of ephemeral inlet formation during extreme events. This study explores the spatiotemporal effects of tides, waves, and storms on flow velocities and morphology of the breach by means of remotely sensed data, geospatial metrics, and a numerical model. The combined use of observations and results from modeling experiments allowed building a conceptual model to explain the life cycle of Pea Island Breach. Wave seasonality dominated the morphological evolution of the inlet by controlling the magnitude and direction of the longshore current that continuously built transient spits at both sides of the breach. Sensitivity analysis to external forcings indicates that ocean waves can modify water levels and velocities in the back barrier. Sound-side storm surge regulates overall growth rate, duration, and decay of peak water levels entering the inlet during extreme events.}, journal={Continental Shelf Research}, publisher={Elsevier BV}, author={Velasquez Montoya, Liliana and Sciaudone, Elizabeth J. and Mitasova, Helena and Overton, Margery F.}, year={2018}, month={Mar}, pages={55–69} }
 @inproceedings{millar_tabrizian_petrasova_petras_harmon_mitasova_meentemeyer_2018, title={Tangible Landscape: A hands-on method for teaching terrain analysis}, volume={2018-April}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046967703&partnerID=MN8TOARS}, DOI={10.1145/3173574.3173954}, abstractNote={This paper presents novel and effective methods for teaching about topography--or shape of terrain--and assessing 3-dimensional spatial learning using tangibles. We used Tangible Landscape--a tangible interface for geospatial modeling--to teach multiple hands-on tangible lessons on the concepts of grading (i.e., earthwork), geomorphology, and hydrology. We examined students' ratings of the system's usability and user experience and tested students' acquisition and transfer of knowledge. Our results suggest the physicality of the objects enabled the participants to effectively interact with the system and each other, positively impacting ratings of usability and task-specific knowledge building. These findings can potentially advance the design and implementation of tangible teaching methods for the topics of geography, design, architecture, and engineering.}, booktitle={Conference on Human Factors in Computing Systems - Proceedings}, author={Millar, G.C. and Tabrizian, P. and Petrasova, A. and Petras, V. and Harmon, B. and Mitasova, H. and Meentemeyer, R.K.}, year={2018} }
 @article{harmon_petrasova_petras_mitasova_meentemeyer_2018, title={Tangible topographic modeling for landscape architects}, volume={16}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85044342339&partnerID=MN8TOARS}, DOI={10.1177/1478077117749959}, abstractNote={ We present Tangible Landscape—a technology for rapidly and intuitively designing landscapes informed by geospatial modeling, analysis, and simulation. It is a tangible interface powered by a geographic information system that gives three-dimensional spatial data an interactive, physical form so that users can naturally sense and shape it. Tangible Landscape couples a physical and a digital model of a landscape through a real-time cycle of physical manipulation, three-dimensional scanning, spatial computation, and projected feedback. Natural three-dimensional sketching and real-time analytical feedback should aid landscape architects in the design of high performance landscapes that account for physical and ecological processes. We conducted a series of studies to assess the effectiveness of tangible modeling for landscape architects. Landscape architecture students, academics, and professionals were given a series of fundamental landscape design tasks—topographic modeling, cut-and-fill analysis, and water flow modeling. We assessed their performance using qualitative and quantitative methods including interviews, raster statistics, morphometric analyses, and geospatial simulation. With tangible modeling, participants built more accurate models that better represented morphological features than they did with either digital or analog hand modeling. When tangibly modeling, they worked in a rapid, iterative process informed by real-time geospatial analytics and simulations. With the aid of real-time simulations, they were able to quickly understand and then manipulate how complex topography controls the flow of water. }, number={1}, journal={International Journal of Architectural Computing}, author={Harmon, B. A. and Petrasova, A. and Petras, Vaclav and Mitasova, Helena and Meentemeyer, R.}, year={2018}, pages={4–21} }
 @article{tonini_shoemaker_petrasova_harmon_petras_cobb_mitasova_meentemeyer_2017, title={Tangible geospatial modeling for collaborative solutions to invasive species management}, volume={92}, ISSN={["1873-6726"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85014320386&partnerID=MN8TOARS}, DOI={10.1016/j.envsoft.2017.02.020}, abstractNote={Managing landscape-scale environmental problems, such as biological invasions, can be facilitated by integrating realistic geospatial models with user-friendly interfaces that stakeholders can use to make critical management decisions. However, gaps between scientific theory and application have typically limited opportunities for model-based knowledge to reach the stakeholders responsible for problem-solving. To address this challenge, we introduce Tangible Landscape, an open-source participatory modeling tool providing an interactive, shared arena for consensus-building and development of collaborative solutions for landscape-scale problems. Using Tangible Landscape, stakeholders gather around a geographically realistic 3D visualization and explore management scenarios with instant feedback; users direct model simulations with intuitive tangible gestures and compare alternative strategies with an output dashboard. We applied Tangible Landscape to the complex problem of managing the emerging infectious disease, sudden oak death, in California and explored its potential to generate co-learning and collaborative management strategies among actors representing stakeholders with competing management aims.}, journal={ENVIRONMENTAL MODELLING & SOFTWARE}, author={Tonini, Francesco and Shoemaker, Douglas and Petrasova, Anna and Harmon, Brendan and Petras, Vaclav and Cobb, Richard C. and Mitasova, Helena and Meentemeyer, Ross K.}, year={2017}, month={Jun}, pages={176–188} }
 @inproceedings{tabrizian_harmon_petrasova_petras_mitasova_meentemeyer_2017, title={Tangible immersion for ecological design}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046940970&partnerID=MN8TOARS}, booktitle={Disciplines and Disruption - Proceedings Catalog of the 37th Annual Conference of the Association for Computer Aided Design in Architecture, ACADIA 2017}, author={Tabrizian, P. and Harmon, B. and Petrasova, A. and Petras, V. and Mitasova, H. and Meentemeyer, R.}, year={2017}, pages={600–609} }
 @article{starek_harmon_mitasova_2016, title={Fort Fisher, NC Past and Present: A Geospatial Analysis using LiDAR and GIS}, ISBN={["978-1-4939-3427-0"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85064763153&partnerID=MN8TOARS}, DOI={10.1007/978-1-4939-3429-4_7}, abstractNote={Fort Fisher was constructed in 1861–1863 by the Confederacy at the mouth of the Cape Fear River in North Carolina to protect the vital trading routes of the seaport at Wilmington. The largest Confederate fort, Ft. Fisher was constructed as an L-shaped fortification consisting of 30 ft (9 m) thick earthen mounds capable of absorbing the shock of a heavy bombardment. In its prime, this fortification consisted of an approximately 1800 ft (550 m) long land face and a mile-long (1.6 km) sea face bounded by two larger 45 ft (14 m) and 60 ft (18 m) high mounds on the southern end. Today, Ft. Fisher is a mere remnant of its former self, with only about one-tenth of the original structure remaining. The region where the fort was constructed is a highly dynamic section of coastline that has undergone extensive shoreline retreat over the past century, resulting in the loss of the majority of the original fortification. Light detection and ranging (LiDAR) survey data and historical maps were used to generate past and present 3-D digital elevation models (DEMs) for both the terrain and fort. The historical shorelines, aerial imagery, bathymetric data and fort models were then integrated and compared within a geographic information system (GIS) to analyze and to model the evolution of the coastline from past to present. Results provide insight into the geographic advantages behind Ft. Fisher’s original layout for defense of the inlet compared to the present day geomorphology of the region.}, journal={MILITARY GEOSCIENCES AND DESERT WARFARE: PAST LESSONS AND MODERN CHALLENGES}, author={Starek, Michael J. and Harmon, Russell S. and Mitasova, Helena}, year={2016}, pages={95–103} }
 @article{tabrizian_petrasova_harmon_petras_mitasova_meentemeyer_2016, title={Immersive Tangible Geospatial Modeling}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85011015621&partnerID=MN8TOARS}, DOI={10.1145/2996913.2996950}, abstractNote={Tangible Landscape is a tangible interface for geographic information systems (GIS). It interactively couples physical and digital models of a landscape so that users can intuitively explore, model, and analyze geospatial data in a collaborative environment. Conceptually Tangible Landscape lets users hold a GIS in their hands so that they can feel the shape of the topography, naturally sculpt new landforms, and interact with simulations like water flow. Since it only affords a bird's-eye view of the landscape, we coupled it with an immersive virtual environment so that users can virtually walk around the modeled landscape and visualize it at a human-scale. Now as users shape topography, draw trees, define viewpoints, or route a walkthrough, they can see the results on the projection-augmented model, rendered on a display, or rendered on a head-mounted display. In this paper we present the Tangible Landscape Immersive Extension, describe its physical setup and software architecture, and demonstrate its features with a case study.}, journal={24TH ACM SIGSPATIAL INTERNATIONAL CONFERENCE ON ADVANCES IN GEOGRAPHIC INFORMATION SYSTEMS (ACM SIGSPATIAL GIS 2016)}, author={Tabrizian, Payam and Petrasova, Anna and Harmon, Brendan and Petras, Vaclav and Mitasova, Helena and Meentemeyer, Ross}, year={2016} }
 @inproceedings{petrasova_petras_van berkel_harmon_mitasova_meentemeyer_2016, title={Open source approachto urban growth simulation}, volume={41}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84979582473&partnerID=MN8TOARS}, DOI={10.5194/isprsarchives-XLI-B7-953-2016}, abstractNote={Spatial patterns of land use change due to urbanization and its impact on the landscape are the subject of ongoing research. Urban growth scenario simulation is a powerful tool for exploring these impacts and empowering planners to make informed decisions. We present FUTURES (FUTure Urban – Regional Environment Simulation) – a patch-based, stochastic, multi-level land change modeling framework as a case showing how what was once a closed and inaccessible model benefited from integration with open source GIS.We will describe our motivation for releasing this project as open source and the advantages of integrating it with GRASS GIS, a free, libre and open source GIS and research platform for the geospatial domain. GRASS GIS provides efficient libraries for FUTURES model development as well as standard GIS tools and graphical user interface for model users. Releasing FUTURES as a GRASS GIS add-on simplifies the distribution of FUTURES across all main operating systems and ensures the maintainability of our project in the future. We will describe FUTURES integration into GRASS GIS and demonstrate its usage on a case study in Asheville, North Carolina. The developed dataset and tutorial for this case study enable researchers to experiment with the model, explore its potential or even modify the model for their applications.}, booktitle={International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives}, author={Petrasova, A. and Petras, V. and Van Berkel, D. and Harmon, B.A. and Mitasova, H. and Meentemeyer, R.K.}, year={2016}, pages={953–959} }
 @inproceedings{jeziorska_mitasova_petrasova_petras_divakaran_zajkowski_2016, title={Overland flow analysis using time series of sUAS- derived elevation models}, volume={3}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84979525774&partnerID=MN8TOARS}, DOI={10.5194/isprs-annals-iii-8-159-2016}, abstractNote={Abstract. With the advent of the innovative techniques for generating high temporal and spatial resolution terrain models from Unmanned Aerial Systems (UAS) imagery, it has become possible to precisely map overland flow patterns. Furthermore, the process has become more affordable and efficient through the coupling of small UAS (sUAS) that are easily deployed with Structure from Motion (SfM) algorithms that can efficiently derive 3D data from RGB imagery captured with consumer grade cameras. We propose applying the robust overland flow algorithm based on the path sampling technique for mapping flow paths in the arable land on a small test site in Raleigh, North Carolina. By comparing a time series of five flights in 2015 with the results of a simulation based on the most recent lidar derived DEM (2013), we show that the sUAS based data is suitable for overland flow predictions and has several advantages over the lidar data. The sUAS based data captures preferential flow along tillage and more accurately represents gullies. Furthermore the simulated water flow patterns over the sUAS based terrain models are consistent throughout the year. When terrain models are reconstructed only from sUAS captured RGB imagery, however, water flow modeling is only appropriate in areas with sparse or no vegetation cover.
                    }, number={8}, booktitle={International archives of the photogrammetry remote sensing and spatial}, author={Jeziorska, J. and Mitasova, Helena and Petrasova, A. and Petras, Vaclav and Divakaran, D. and Zajkowski, T.}, year={2016}, pages={159–166} }
 @inproceedings{petras_petrasova_jeziorska_mitasova_2016, title={Processing UAV and LiDAR point clouds in grass GIS}, volume={41}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84979529878&partnerID=MN8TOARS}, DOI={10.5194/isprsarchives-XLI-B7-945-2016}, abstractNote={Today’s methods of acquiring Earth surface data, namely lidar and unmanned aerial vehicle (UAV) imagery, non-selectively collect or generate large amounts of points. Point clouds from different sources vary in their properties such as number of returns, density, or quality. We present a set of tools with applications for different types of points clouds obtained by a lidar scanner, structure from motion technique (SfM), and a low-cost 3D scanner. To take advantage of the vertical structure of multiple return lidar point clouds, we demonstrate tools to process them using 3D raster techniques which allow, for example, the development of custom vegetation classification methods. Dense point clouds obtained from UAV imagery, often containing redundant points, can be decimated using various techniques before further processing. We implemented and compared several decimation techniques in regard to their performance and the final digital surface model (DSM). Finally, we will describe the processing of a point cloud from a low-cost 3D scanner, namely Microsoft Kinect, and its application for interaction with physical models. All the presented tools are open source and integrated in GRASS GIS, a multi-purpose open source GIS with remote sensing capabilities. The tools integrate with other open source projects, specifically Point Data Abstraction Library (PDAL), Point Cloud Library (PCL), and OpenKinect libfreenect2 library to benefit from the open source point cloud ecosystem. The implementation in GRASS GIS ensures long term maintenance and reproducibility by the scientific community but also by the original authors themselves.}, booktitle={International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives}, author={Petras, V. and Petrasova, A. and Jeziorska, J. and Mitasova, H.}, year={2016}, pages={945–952} }
 @article{gilmore_genereux_solomon_farrell_mitasova_2016, title={Quantifying an aquifer nitrate budget and future nitrate discharge using field data from streambeds and well nests}, volume={52}, ISSN={["1944-7973"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85005896258&partnerID=MN8TOARS}, DOI={10.1002/2016wr018976}, abstractNote={Abstract}, number={11}, journal={WATER RESOURCES RESEARCH}, author={Gilmore, Troy E. and Genereux, David P. and Solomon, D. Kip and Farrell, Kathleen M. and Mitasova, Helena}, year={2016}, month={Nov}, pages={9046–9065} }
 @article{gilmore_genereux_solomon_solder_kimball_mitasova_birgand_2016, title={Quantifying the fate of agricultural nitrogen in an unconfined aquifer: Stream-based observations at three measurement scales}, volume={52}, ISSN={0043-1397}, url={http://dx.doi.org/10.1002/2015WR017599}, DOI={10.1002/2015wr017599}, abstractNote={Abstract}, number={3}, journal={Water Resources Research}, publisher={American Geophysical Union (AGU)}, author={Gilmore, Troy E. and Genereux, David P. and Solomon, D. Kip and Solder, John E. and Kimball, Briant A. and Mitasova, Helena and Birgand, François}, year={2016}, month={Mar}, pages={1961–1983} }
 @inproceedings{harmon_petrasova_petras_mitasova_meentemeyer_2016, title={Tangible landscape: Cognitively grasping the flowofwater}, volume={41}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84981276026&partnerID=MN8TOARS}, DOI={10.5194/isprsarchives-XLI-B2-647-2016}, abstractNote={Complex spatial forms like topography can be challenging to understand, much less intentionally shape, given the heavy cognitive load of visualizing and manipulating 3D form. Spatiotemporal processes like the flow of water over a landscape are even more challenging to understand and intentionally direct as they are dependent upon their context and require the simulation of forces like gravity and momentum. This cognitive work can be offloaded onto computers through 3D geospatial modeling, analysis, and simulation. Interacting with computers, however, can also be challenging, often requiring training and highly abstract thinking. Tangible computing – an emerging paradigm of human-computer interaction in which data is physically manifested so that users can feel it and directly manipulate it – aims to offload this added cognitive work onto the body. We have designed Tangible Landscape, a tangible interface powered by an open source geographic information system (GRASS GIS), so that users can naturally shape topography and interact with simulated processes with their hands in order to make observations, generate and test hypotheses, and make inferences about scientific phenomena in a rapid, iterative process. Conceptually Tangible Landscape couples a malleable physical model with a digital model of a landscape through a continuous cycle of 3D scanning, geospatial modeling, and projection. We ran a flow modeling experiment to test whether tangible interfaces like this can effectively enhance spatial performance by offloading cognitive processes onto computers and our bodies. We used hydrological simulations and statistics to quantitatively assess spatial performance. We found that Tangible Landscape enhanced 3D spatial performance and helped users understand water flow.}, booktitle={International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives}, author={Harmon, B.A. and Petrasova, A. and Petras, V. and Mitasova, H. and Meentemeyer, R.K.}, year={2016}, pages={647–653} }
 @inproceedings{harmon_petrasova_petras_mitasova_meentemeyer_2016, title={Tangible landscape: cognitively grasping the flow of water}, volume={41}, DOI={10.5194/isprs-archives-xli-b2-647-2016}, abstractNote={Abstract. Complex spatial forms like topography can be challenging to understand, much less intentionally shape, given the heavy cognitive load of visualizing and manipulating 3D form. Spatiotemporal processes like the flow of water over a landscape are even more challenging to understand and intentionally direct as they are dependent upon their context and require the simulation of forces like gravity and momentum. This cognitive work can be offloaded onto computers through 3D geospatial modeling, analysis, and simulation. Interacting with computers, however, can also be challenging, often requiring training and highly abstract thinking. Tangible computing – an emerging paradigm of human-computer interaction in which data is physically manifested so that users can feel it and directly manipulate it – aims to offload this added cognitive work onto the body. We have designed Tangible Landscape, a tangible interface powered by an open source geographic information system (GRASS GIS), so that users can naturally shape topography and interact with simulated processes with their hands in order to make observations, generate and test hypotheses, and make inferences about scientific phenomena in a rapid, iterative process. Conceptually Tangible Landscape couples a malleable physical model with a digital model of a landscape through a continuous cycle of 3D scanning, geospatial modeling, and projection. We ran a flow modeling experiment to test whether tangible interfaces like this can effectively enhance spatial performance by offloading cognitive processes onto computers and our bodies. We used hydrological simulations and statistics to quantitatively assess spatial performance. We found that Tangible Landscape enhanced 3D spatial performance and helped users understand water flow.
                    }, number={B2}, booktitle={International archives of the photogrammetry remote sensing and spatial}, author={Harmon, B. A. and Petrasova, A. and Petras, Vaclav and Mitasova, Helena and Meentemeyer, K.}, year={2016}, pages={647–653} }
 @article{lyons_starek_wegmann_mitasova_2015, title={Bank erosion of legacy sediment at the transition from vertical to lateral stream incision}, volume={40}, ISSN={["1096-9837"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84943362977&partnerID=MN8TOARS}, DOI={10.1002/esp.3753}, abstractNote={Abstract}, number={13}, journal={EARTH SURFACE PROCESSES AND LANDFORMS}, author={Lyons, Nathan J. and Starek, Michael J. and Wegmann, Karl W. and Mitasova, Helena}, year={2015}, month={Oct}, pages={1764–1778} }
 @article{petras_petrasova_harmon_meentemeyer_mitasova_2015, title={Integrating Free and Open Source Solutions into Geospatial Science Education}, volume={4}, ISSN={["2220-9964"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84948970902&partnerID=MN8TOARS}, DOI={10.3390/ijgi4020942}, abstractNote={While free and open source software becomes increasingly important in geospatial research and industry, open science perspectives are generally less reflected in universities’ educational programs. We present an example of how free and open source software can be incorporated into geospatial education to promote open and reproducible science. Since 2008 graduate students at North Carolina State University have the opportunity to take a course on geospatial modeling and analysis that is taught with both proprietary and free and open source software. In this course, students perform geospatial tasks simultaneously in the proprietary package ArcGIS and the free and open source package GRASS GIS. By ensuring that students learn to distinguish between geospatial concepts and software specifics, students become more flexible and stronger spatial thinkers when choosing solutions for their independent work in the future. We also discuss ways to continually update and improve our publicly available teaching materials for reuse by teachers, self-learners and other members of the GIS community. Only when free and open source software is fully integrated into geospatial education, we will be able to encourage a culture of openness and, thus, enable greater reproducibility in research and development applications.}, number={2}, journal={ISPRS INTERNATIONAL JOURNAL OF GEO-INFORMATION}, author={Petras, Vaclav and Petrasova, Anna and Harmon, Brendan and Meentemeyer, Ross K. and Mitasova, Helena}, year={2015}, month={Jun}, pages={942–956} }
 @book{petrasova_petras_harmon_mitasova_2015, title={Tangible modeling with open source GIS}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85012134759&partnerID=MN8TOARS}, DOI={10.1007/978-3-319-25775-4}, abstractNote={This book presents a new type of modeling environment where users interact with geospatial simulations using 3D physical models of studied landscapes. Multiple users can alter the physical model by ha}, journal={Tangible Modeling with Open Source GIS}, author={Petrasova, A. and Petras, V. and Harmon, B. and Mitasova, H.}, year={2015}, pages={1–135} }
 @article{paris_mitasova_2014, title={Barrier island dynamics using mass center analysis: A new way to detect and track large-scale change}, volume={3}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84948740266&partnerID=MN8TOARS}, DOI={10.3390/ijgi3010049}, abstractNote={A geographic information system (GIS) was used to introduce and test a new method for quantitatively characterizing topographic change. Borrowing from classic Newtonian mechanics, the concept of a body’s center of mass is applied to the geomorphic landscape, and the barrier island environment in particular, to evaluate the metric’s potential as a proxy for detecting, tracking and visualizing change. Two barrier islands along North Carolina’s Outer Banks are used to test this idea: Core Banks, uninhabited and largely-undeveloped, and Hatteras Island, altered by the presence of a protective dune system. Findings indicate that for Core Banks, the alongshore change in the center of mass is in accord with dominate littoral transport and wind conditions. Cross-shore change agrees with independent estimates for the island migration rates. This lends credence to our assertion that the mass center metric has the potential to be a viable proxy for describing wholesale barrier migration and would be a valuable addition to the already-established ocean shoreline and subaerial volume metrics. More research is, however, required to demonstrate efficacy.}, number={1}, journal={ISPRS International Journal of Geo-Information}, author={Paris, P. and Mitasova, H.}, year={2014}, pages={49–65} }
 @inbook{hardin_mitasova_tateosian_overton_2014, title={Feature extraction and feature change metrics}, volume={0}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85045013232&partnerID=MN8TOARS}, DOI={10.1007/978-1-4939-1835-5_4}, abstractNote={Coastal change has been historically measured by metrics derived for specific coastal linear features such as shorelines. Linear features are also important for measuring sand dune migration based on the location of dune crests and slip faces and for prediction of coastal vulnerability. In this chapter we present methods for extracting shorelines, dune ridges, dune crests and building footprints from DEMs. Then we measure the change of these features and use them to map vulnerability to storms.}, number={9781493918348}, booktitle={SpringerBriefs in Computer Science}, author={Hardin, E. and Mitasova, H. and Tateosian, L. and Overton, M.}, year={2014}, pages={35–62} }
 @inproceedings{petrasova_harmon_petras_mitasova_2014, title={GIS-based environmental modeling with tangible interaction and dynamic visualization}, volume={2}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84911897646&partnerID=MN8TOARS}, booktitle={Proceedings - 7th International Congress on Environmental Modelling and Software: Bold Visions for Environmental Modeling, iEMSs 2014}, author={Petrasova, A. and Harmon, B. and Petras, V. and Mitasova, H.}, year={2014}, pages={758–765} }
 @article{lyons_mitasova_wegmann_2014, title={Improving mass-wasting inventories by incorporating debris flow topographic signatures}, volume={11}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84902003440&partnerID=MN8TOARS}, DOI={10.1007/s10346-013-0398-0}, number={3}, journal={Landslides}, author={Lyons, N.J. and Mitasova, Helena and Wegmann, K.W.}, year={2014}, pages={385–397} }
 @inbook{hardin_mitasova_tateosian_overton_2014, title={Introduction}, volume={0}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85045018146&partnerID=MN8TOARS}, DOI={10.1007/978-1-4939-1835-5_1}, abstractNote={Management of highly dynamic coastal landscapes requires repeated mapping and analysis of observed changes. Modern remote sensing techniques, such as lidar, increased the frequency and level of detail in coastal surveys and new methods were developed to extract valuable information from these data using Geographic Information Systems (GIS). In this chapter we discuss mapping of coastal change, on-line data resources, and the basics of installation and working with open source GRASS GIS used in this book.}, number={9781493918348}, booktitle={SpringerBriefs in Computer Science}, author={Hardin, E. and Mitasova, H. and Tateosian, L. and Overton, M.}, year={2014}, pages={1–6} }
 @inbook{hardin_mitasova_tateosian_overton_2014, title={Processing coastal lidar time series}, volume={0}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84990851417&partnerID=MN8TOARS}, DOI={10.1007/978-1-4939-1835-5_2}, abstractNote={In this chapter, we analyze time series of lidar data point clouds to assess the point density, gaps in coverage, spatial extent and accuracy. Based on this analysis and a given application we select appropriate resolution and interpolation method for computation of raster-based digital elevation model (DEM). We explain computation of DEMs by per raster-cell averaging, two types of splines. Assessment of systematic error using geodetic benchmarks or other ground truth point data and correction of any shifted DEMs is the final step in creating a consistent DEM time series.}, number={9781493918348}, booktitle={SpringerBriefs in Computer Science}, author={Hardin, E. and Mitasova, H. and Tateosian, L. and Overton, M.}, year={2014}, pages={7–25} }
 @inbook{hardin_mitasova_tateosian_overton_2014, title={Raster-based analysis}, volume={0}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84990851424&partnerID=MN8TOARS}, DOI={10.1007/978-1-4939-1835-5_3}, abstractNote={Raster-based analysis on two or more DEMs can provide information about change patterns and trends. A common approach to mapping elevation change between two surveys is DEM differencing, performed by map algebra within GIS (r.mapcalc in GRASS). For a larger number of elevation data snapshots, per cell statistics can be applied to the raster DEMs to derive summary maps, which reveal the spatial patterns of stable and dynamic sites, the time periods when sites reach their highest or lowest elevations, and the trends in elevation change.}, number={9781493918348}, booktitle={SpringerBriefs in Computer Science}, author={Hardin, E. and Mitasova, H. and Tateosian, L. and Overton, M.}, year={2014}, pages={27–34} }
 @article{tateosian_mitasova_thakur_hardin_russ_blundell_2014, title={Visualizations of coastal terrain time series}, volume={13}, ISSN={["1473-8724"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84906534191&partnerID=MN8TOARS}, DOI={10.1177/1473871613487086}, abstractNote={ In coastal regions, water, wind, gravitation, vegetation, and human activity continuously alter landscape surfaces. Visualizations are important for understanding coastal landscape evolution and its driving processes. Visualizing change in highly dynamic coastal terrain poses a formidable challenge; the combination of natural and anthropogenic forces leads to cycles of retreat and recovery and complex morphology of landforms. In recent years, repeated high-resolution laser terrain scans have generated a time series of point cloud data that represent landscapes at snapshots in time, including the impacts of major storms. In this article, we build on existing approaches for visualizing spatial–temporal data to create a collection of perceptual visualizations to support coastal terrain evolution analysis. We extract terrain features and track their migration; we derive temporal summary maps and heat graphs that quantify the pattern of elevation change and sediment redistribution and use the space–time cube concept to create visualizations of terrain evolution. The space–time cube approach allows us to represent shoreline evolution as an isosurface extracted from a voxel model created by stacking time series of digital elevation models. We illustrate our approach on a series of Light Detection and Ranging surveys of sandy North Carolina barrier islands. Our results reveal terrain changes of shoreline and dune ridge migration, dune breaches and overwash, the formation of new dune ridges, and the construction and destruction of homes, changes which are due to erosion and accretion, hurricanes, and human activities. These events are all visualized within their geographic and temporal contexts. }, number={3}, journal={INFORMATION VISUALIZATION}, author={Tateosian, Laura and Mitasova, Helena and Thakur, Sidharth and Hardin, Eric and Russ, Emily and Blundell, Bruce}, year={2014}, month={Jul}, pages={266–282} }
 @inbook{hardin_mitasova_tateosian_overton_2014, title={Visualizing coastal change}, volume={0}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85045013018&partnerID=MN8TOARS}, DOI={10.1007/978-1-4939-1835-5_6}, abstractNote={Scientific visualization provides a means for effective analysis and communication of complex information that may be otherwise difficult to explain and explore. This particularly applies to coastal geomorphology, where 3D spatial and temporal patterns and relationships are critical for capturing landscape features and their dynamics. In this chapter we present GIS-based techniques for visualizing dynamic coastal landscapes using 2D maps, 3D perspective views, animations, and the space-time cube approach.}, number={9781493918348}, booktitle={SpringerBriefs in Computer Science}, author={Hardin, E. and Mitasova, H. and Tateosian, L. and Overton, M.}, year={2014}, pages={71–80} }
 @inbook{hardin_mitasova_tateosian_overton_2014, title={Volume analysis}, volume={0}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85045012430&partnerID=MN8TOARS}, DOI={10.1007/978-1-4939-1835-5_5}, number={9781493918348}, booktitle={SpringerBriefs in Computer Science}, author={Hardin, E. and Mitasova, H. and Tateosian, L. and Overton, M.}, year={2014}, pages={63–70} }
 @book{mitasova_barton_ullah_hofierka_harmon_2013, title={GIS-Based Soil Erosion Modeling}, volume={3}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84903414788&partnerID=MN8TOARS}, DOI={10.1016/B978-0-12-374739-6.00052-X}, abstractNote={This chapter explains the theory and methods for GIS-based modeling of soil erosion, sediment transport, and deposition by surface water flow. The mathematical foundations of erosion models are introduced and simplified equations, suitable for GIS implementation, are derived. The presented methods cover modeling of hillslope erosion and deposition, gully formation, and landscape evolution processes. Coupling of erosion models with GIS is discussed, followed by examples of GIS implementation of simple and advanced models. The concepts and methods are illustrated using two case studies, that focus on feedbacks between the human activity and landscape processes.}, journal={Treatise on Geomorphology}, author={Mitasova, H. and Barton, M. and Ullah, I. and Hofierka, J. and Harmon, R.S.}, year={2013}, pages={228–258} }
 @article{paris_starek_hardin_kurum_overton_mitasova_2013, title={Lines in the Sand: Geomorphic and Geospatial Characterization and Interpretation of Sandy Shorelines and Beaches}, volume={7}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84878461269&partnerID=MN8TOARS}, DOI={10.1111/gec3.12041}, abstractNote={Abstract}, number={5}, journal={Geography Compass}, author={Paris, P. and Starek, M.J. and Hardin, E. and Kurum, O. and Overton, M. and Mitasova, H.}, year={2013}, pages={315–343} }
 @article{mitas_mitasova_brothers_weaver_2013, title={Managing dune landscape changes at Jockey's Ridge State Park, North Carolina}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84893504743&partnerID=MN8TOARS}, DOI={10.3727/154427313X13818453739477}, abstractNote={Coastal dunes are challenging to manage due to their dynamic nature, vulnerable ecosystems, and recreational demand. A limited management approach was studied at Jockey's Ridge, the largest active dune on the US Atlantic coast. Visitor experience data, digital elevation models, and
 informal stories and photos were integrated in a case study approach. Data revealed the value of an integrated management approach that preserved the dune as a unique “living” geomorphological feature with interventions limited to the park borders. The accessibility of the dune
 to visitors facilitated intense, enjoyable interactions with nature. Elevation data show that the management approach has maintained the dune's unique naturally dynamic character, revealing the benefits of preserving processes rather than features.}, number={3-4}, journal={Tourism in Marine Environments}, author={Mitas, O. and Mitasova, H. and Brothers, G. and Weaver, K.}, year={2013}, pages={155–167} }
 @article{mitasova_schweik_2013, title={Open source geospatial education and research}, volume={27}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84885105445&partnerID=MN8TOARS}, number={8}, journal={GIM International}, author={Mitasova, H. and Schweik, C.}, year={2013}, pages={25–28} }
 @article{thakur_tateosian_mitasova_hardin_overton_2013, title={SUMMARY VISUALIZATIONS FOR COASTAL SPATIAL-TEMPORAL DYNAMICS}, volume={3}, ISSN={["2152-5099"]}, DOI={10.1615/int.j.uncertaintyquantification.2012003969}, abstractNote={Digital scans of dynamic terrains such as coastal regions are now being gathered at high spatial and temporal resolution. Although standard tools based on geographic information systems (GIS) are indispensable for analyzing geospatial data, they have limited support to display time-dependent changes in data and information such as statistical distributions and uncertainty in data. We present a set of techniques for visually summarizing the dynamics of coastal dunes. We visualize summary statistics of important data attributes and risk or vulnerability indices as functions of both spatial and temporal dimensions in our data and represent uncertainty in the data set. We apply standard techniques, the space time cube and clustering, in novel ways to the domain of geomorphology. We combine surface-mapping and imagery with summary visualizations to retain important geographical context in the visualizations and reduce clutter due to direct plotting of statistical data in displays of geospatial information. We also address some issues pertaining to visualization of summary statistics for geographical regions at varying scales. We demonstrate visualization tools on time series of elevation models from the Outer Banks of North Carolina and observe temporal-spatial trends therein.}, number={3}, journal={INTERNATIONAL JOURNAL FOR UNCERTAINTY QUANTIFICATION}, author={Thakur, Sidharth and Tateosian, Laura and Mitasova, Helena and Hardin, Eric and Overton, Margery}, year={2013}, pages={241–253} }
 @article{starek_mitasova_wegmann_lyons_2013, title={Space-Time Cube Representation of Stream Bank Evolution Mapped by Terrestrial Laser Scanning}, volume={10}, ISSN={["1558-0571"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84886592528&partnerID=MN8TOARS}, DOI={10.1109/lgrs.2013.2241730}, abstractNote={Terrestrial laser scanning (TLS) is utilized to monitor bank erosion along a stream that has incised through historic millpond (legacy) sediment. A processing workflow is developed to generate digital terrain models (DTMs) of the bank's surface from the TLS point cloud data. Differencing of the DTMs reveals that the majority of sediment loss stems from the legacy sediment layer. The DTM time series is stacked into a voxel model to form a space-time cube (STC). The STC provides a compact representation of the bank's spatiotemporal evolution captured by the TLS scans. The continuous STC extends this approach by generating a voxel model with equal temporal resolution directly from the point cloud data. Novel visualizations are extracted from the STCs to explore patterns in surface evolution. Results show that erosion is highly variable in space and time, with large-scale erosion being episodic due to bank failure within legacy sediment.}, number={6}, journal={IEEE GEOSCIENCE AND REMOTE SENSING LETTERS}, author={Starek, M. J. and Mitasova, H. and Wegmann, K. W. and Lyons, N.}, year={2013}, month={Nov}, pages={1369–1373} }
 @article{harmon_lyons_gardner_goldsmith_long_mitasova_welch_welch_2013, title={Surface water geochemistry and chemical weathering across Panama}, volume={7}, ISSN={["1878-5220"]}, DOI={10.1016/j.proeps.2013.03.134}, abstractNote={Abstract A geochemical study of rivers and streams was undertaken across Panama during 2005-09, from the Lago Bayano area in the east to the Costa Rican border in the west. Low overall dissolved solute contents (TDS = 145±160 mg/L) suggest a short residence time for infiltrating precipitation in the weathering zone. Watershed lithology exerts the main control on riverine chemistry, with streams on marine sedimentary rocks having higher dissolved solids loads than those on igneous rocks, with the latter exhibiting the highest silica contents and increasing trends of total cations with increasing dissolved silica. This feature and the large degree of compositional overlap between large rivers and small tributary streams implies that chemical weathering of silicate materials in the soil zone is the predominant process determining the geochemistry of streams and rivers in this tropical environment. Silicate weathering rates (Casil+Mgsil+Na+K) range over more than an order in magnitude from 2.5 to 28.4 tons/km2/y, whilst H4SiO4 yields range from 7.1 to 65 tons/km2/y. Basin-wide CO2 consumption yields by silicate weathering, calculated from total cation content (corrected for sea salt contribution), basin area and discharge, are high on a global basis.}, journal={PROCEEDINGS OF THE FOURTEENTH INTERNATIONAL SYMPOSIUM ON WATER-ROCK INTERACTION, WRI 14}, author={Harmon, Russell S. and Lyons, W. Berry and Gardner, Christopher B. and Goldsmith, Steven T. and Long, David T. and Mitasova, Helena and Welch, Susan and Welch, Kathy}, year={2013}, pages={342–345} }
 @article{brovelli_mitasova_neteler_raghavan_2012, title={Free and open source desktop and Web GIS solutions}, volume={4}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84867367774&partnerID=MN8TOARS}, DOI={10.1007/s12518-012-0082-4}, abstractNote={Community-based development through collaboration amongst software developers and researchers distributed globally has led to a wealth of feature-rich applications of Free and Open Source Software for Geoinformatics (FOSS4G). In the FOSS4G, development model online source code repository, mailing lists, and a Wiki provide the software developers and users with a virtual and ubiquitous platform for the implementation of new methods, algorithms, and tools as well as for refinement and enhancements of the existing code. For end users, this development model provides highly interoperable, sophisticated software at no cost. This approach is both flexible and immune to vendor lock-ins. Further, the reproducibility of results and quality assessment of methods is greatly facilitated since full access to the underlying algorithms is guaranteed. The source code is typically published under free and open source software licenses with end-user rights to run the program for any purpose, to study how the program works, to adapt it, and to redistribute copies including modifications. The FOSS4G offers software libraries for map projection and data format conversion, desktop Geographic Information Systems (GIS), Web mapping/Web–GIS, spatial databases, geostatistics, and metadata catalogues. Most FOSS4G software packages run natively on common operating systems and may be installed and used without restriction in any commercial or non-commercial environment at no cost for the end users. Open Source Geospatial Foundation (OSGeo, http:// www.osgeo.org) serves as an umbrella organization whose mission is to support the collaborative development of FOSS4G and promote their widespread use. OSGeo provides a common forum and shared infrastructure for improving cross-project collaboration. Acceptance of a project to OSGeo depends on a successful incubation process which includes a detailed source code audit to identify any license incompatibilities in the code. This incubation process also confirms that the project is supported by a healthy community, including validation of the rules and processes governing the project's management. Since its inception in 2006, OSGeo has been providing organizational support for building a vibrant international community to advance geospatial technologies and solutions using open source software, open data and open standards. This special issue is brought forth with the aim of presenting the rich capabilities of FOSS4G to foster original research and enable deployment of innovative solutions. The issue covers a broad range of topics, highlighting the diversity of methods, tools, and applications of FOSS4G. The first two papers introduce new tools and applications for vegetation analysis, first as a M. A. Brovelli (*) Environmental, Hydraulic, Infrastructures and Surveying Engineering Department, Politecnico di Milano-Campus Como, Via Natta 12/14, 22100 Como, Italy e-mail: maria.brovelli@polimi.it}, number={2}, journal={Applied Geomatics}, author={Brovelli, M.A. and Mitasova, H. and Neteler, M. and Raghavan, V.}, year={2012}, pages={65–66} }
 @inproceedings{hardin_mitasova_overton_2012, title={GIS-based analysis of storm vulnerability change at Pea Island, NC}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85088756302&partnerID=MN8TOARS}, DOI={10.9753/icce.v33.management.75}, abstractNote={In August 2011, Hurricane Irene opened multiple small breaches along the Outer Banks of North Carolina, USA. To predict storm damage to barrier islands, the United States Geological Survey (USGS) has developed the storm impact scale for barrier islands, which assesses vulnerability based on the configuration of the pre-storm terrain relative to storm characteristics. We present the vulnerability of Pea Island to Hurricane Isabel (2003) and Irene (2011) using an efficient GIS-based implementation of the storm impact scale. This implementation employs a least cost path approach to automated topographic feature extraction and a remote sensing approach to wrack line extraction for storm parameter estimation. The assessed vulnerability along with high-resolution topographic visualizations based on a decadal time-series of Light Detection and Ranging (LiDAR) data suggest that the location of the breach formation was a function of the pre-storm terrain. With the presented methodology, the geospatial information required to identify vulnerable areas can efficiently be extracted so that management strategies can be implemented before storm damage occurs.}, booktitle={Proceedings of the Coastal Engineering Conference}, author={Hardin, E. and Mitasova, H. and Overton, M.}, year={2012} }
 @inproceedings{kurum_overton_mitasova_2012, title={Land cover and sediment layers as controls of inlet breaching}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85074086096&partnerID=MN8TOARS}, DOI={10.9753/icce.v33.sediment.114}, abstractNote={Understanding the processes that take place during a storm leading to coastal morphological change has been a challenging topic for coastal engineers. Over the years, many models have been developed to predict the coastal response to storms evolving from the one dimensional empirical models to two or three dimensional process based models. We hypothesized that the predictive capacity of these models can be improved by incorporating the site specific effect of the land cover features that are in place at the time of the storm. In this work, we present a case study of the development of the Pea Island breach, Outer Banks, North Carolina during Hurricane Irene in August 2011. The inclusion of the land cover effects into the model significantly improves the predictive capability of the model results.}, booktitle={Proceedings of the Coastal Engineering Conference}, author={Kurum, M.O. and Overton, M. and Mitasova, H.}, year={2012} }
 @article{hardin_kurum_mitasova_overton_2012, title={Least cost path extraction of topographic features for storm impact scale mapping}, volume={28}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84864257257&partnerID=MN8TOARS}, DOI={10.2112/JCOASTRES-D-11-00126.1}, abstractNote={Abstract Hardin, E.; Kurum, M.O.; Mitasova, H., and Overton, M.F., 2012. Least cost path extraction of topographic features for storm impact scale mapping. A raster-based, spatially distributed implementation of the storm impact scale, designed to assess barrier island vulnerability, is presented. The two core topographic parameters of the scale, dune ridge and dune toe elevation, are extracted from a high-resolution, light detection and ranging (LIDAR)-derived digital elevation model (DEM). In addition, the beach slope, necessary to compute wave run-up, is extracted from the beach face. Innovative implementation of least cost path analysis and a physics-based model of an elastic sheet are used to map the dune ridge and dune toe. The robustness and efficiency of the topographic feature extraction method is demonstrated along 4 km of shoreline in Pea Island, Outer Banks, North Carolina.}, number={4}, journal={Journal of Coastal Research}, author={Hardin, E. and Kurum, M.O. and Mitasova, Helena and Overton, M.F.}, year={2012}, pages={970–978} }
 @article{barton_ullah_bergin_mitasova_sarjoughian_2012, title={Looking for the future in the past: Long-term change in socioecological systems}, volume={241}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84864065978&partnerID=MN8TOARS}, DOI={10.1016/j.ecolmodel.2012.02.010}, abstractNote={The archaeological record has been described as a key to the long-term consequences of human action that can help guide our decisions today. Yet the sparse and incomplete nature of this record often makes it impossible to inferentially reconstruct past societies in sufficient detail for them to serve as more than very general cautionary tales of coupled socio-ecological systems. However, when formal and computational modeling is used to experimentally simulate human socioecological dynamics, the empirical archaeological record can be used to validate and improve dynamic models of long term change. In this way, knowledge generated by archaeology can play a unique and valuable role in developing the tools to make more informed decisions that will shape our future. The Mediterranean Landscape Dynamics project offers an example of using the past to develop and test computational models of interactions between land-use and landscape evolution that ultimately may help guide decision-making.}, journal={Ecological Modelling}, author={Barton, C.M. and Ullah, I.I.T. and Bergin, S.M. and Mitasova, H. and Sarjoughian, H.}, year={2012}, pages={42–53} }
 @inbook{jolma_ames_horning_mitasova_neteler_racicot_sutton_2012, title={Open-source tools for environmental modeling}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85022204348&partnerID=MN8TOARS}, DOI={10.1007/978-3-540-72680-7_31}, abstractNote={Environmental modeling and management is an important application area for geographic information. At Geographic Information (GI) the outset of a modeling or management project, the location of the study is explored and existing data are mapped and visualized. When the project progresses, data need to be stored and equations need Free and Open-Source Software (FOSS) to be implemented. Free and open-source software (FOSS) provides tools that are shared by their developers to be used, studied, extended, and redistributed. The total body of FOSS is already enormous and includes a substantial collection of geospatial software. FOSS is maintained and developed further by a community, which can be freely joined and which appreciates OSGeo foundation contributions. The geospatial FOSS community, represented by the OSGeo foundation, develops several software products that can be linked together, to environmental models, and to other software. The software platform for environmental modeling and management is a set of tools and a set of FOSS (Free and Open Software) modeling tool R Python services. Generic FOSS modeling tools, such as R and Python, have been made geospatially aware by geospatial FOSS geospatial FOSS libraries. Geospatial FOSS constitutes platforms for developing applications for environmental management. It supports web services well, which is an important part of the geospatial platform.}, booktitle={Springer Handbook of Geographic Information}, author={Jolma, A. and Ames, D.P. and Horning, N. and Mitasova, H. and Neteler, M. and Racicot, A. and Sutton, T.}, year={2012}, pages={967–984} }
 @article{mitasova_harmon_weaver_lyons_overton_2012, title={Scientific visualization of landscapes and landforms}, volume={137}, ISSN={["1872-695X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-82455187995&partnerID=MN8TOARS}, DOI={10.1016/j.geomorph.2010.09.033}, abstractNote={Scientific visualization of geospatial data provides highly effective tools for analysis and communication of information about the land surface and its features, properties, and temporal evolution. Whereas single-surface visualization of landscapes is now routinely used in presentation of Earth surface data, interactive 3D visualization based upon multiple elevation surfaces and cutting planes is gaining recognition as a powerful tool for analyzing landscape structure based on multiple return Light Detection and Ranging (LiDAR) data. This approach also provides valuable insights into land surface changes captured by multi-temporal elevation models. Thus, animations using 2D images and 3D views are becoming essential for communicating results of landscape monitoring and computer simulations of Earth processes. Multiple surfaces and 3D animations are also used to introduce novel concepts for visual analysis of terrain models derived from time-series of LiDAR data using multi-year core and envelope surfaces. Analysis of terrain evolution using voxel models and visualization of contour evolution using isosurfaces has potential for unique insights into geometric properties of rapidly evolving coastal landscapes. In addition to visualization on desktop computers, the coupling of GIS with new types of graphics hardware systems provides opportunities for cutting-edge applications of visualization for geomorphological research. These systems include tangible environments that facilitate intuitive 3D perception, interaction and collaboration. Application of the presented visualization techniques as supporting tools for analyses of landform evolution using airborne LiDAR data and open source geospatial software is illustrated by two case studies from North Carolina, USA.}, number={1}, journal={GEOMORPHOLOGY}, author={Mitasova, Helena and Harmon, Russell S. and Weaver, Katherine J. and Lyons, Nathan J. and Overton, Margery F.}, year={2012}, month={Jan}, pages={122–137} }
 @article{alvarez_mitasova_allen_2011, title={ESTIMATING MONTHLY SOLAR RADIATION IN SOUTH-CENTRAL CHILE}, volume={71}, ISSN={["0718-5820"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84255171688&partnerID=MN8TOARS}, DOI={10.4067/s0718-58392011000400016}, abstractNote={La radiacion solar es un componente clave en los modelos basados en procesos. La cantidad de esta energia depende de la ubicacion, epoca del ano, y tambien de las condiciones atmosfericas. Varias ecuaciones y modelos han sido desarrollados para diferentes condiciones, utilizando datos historicos de las redes de estaciones meteorologicas o de las mediciones por satelite. Sin embargo, las estimaciones de la radiacion solar son demasiado locales con estaciones meteorologicas, o con una resolucion muy gruesa cuando se trabaja con satelites. En el presente estudio se estimo radiacion solar global mensual para la region centro sur de Chile mediante el uso del modelo r.sun y se valido con observaciones de estaciones meteorologicas automaticas. Se analizo el desempeno de los resultados de la irradiacion global con los modelos Hargreaves-Samani (HS) y Bristol-Campbell (BC). Las estimaciones del modelo calibrado r.sun explican un 89% de la varianza (r2 = 0.89) en valores medios mensuales observados. El modelo se comporto muy bien para una amplia zona de las condiciones de Chile, comparados con los modelos HS y BC. Nuestras estimaciones de la radiacion global utilizando el modelo r.sun podrian ser mejoradas aun mas con una posterior calibracion a partir de observaciones y una mejor estimacion de la nubosidad en la medida que esten disponibles. Con procedimientos adicionales, el modelo r.sun podria ser utilizado para proporcionar estimaciones espaciales de la radiacion solar diaria, semanal, mensual, y anual.}, number={4}, journal={CHILEAN JOURNAL OF AGRICULTURAL RESEARCH}, author={Alvarez, Jose and Mitasova, Helena and Allen, H. Lee}, year={2011}, pages={601–609} }
 @article{metz_mitasova_harmon_2011, title={Efficient extraction of drainage networks from massive, radar-based elevation models with least cost path search}, volume={15}, ISSN={["1607-7938"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-79952172297&partnerID=MN8TOARS}, DOI={10.5194/hess-15-667-2011}, abstractNote={Abstract. The availability of both global and regional elevation datasets acquired by modern remote sensing technologies provides an opportunity to significantly improve the accuracy of stream mapping, especially in remote, hard to reach regions. Stream extraction from digital elevation models (DEMs) is based on computation of flow accumulation, a summary parameter that poses performance and accuracy challenges when applied to large, noisy DEMs generated by remote sensing technologies. Robust handling of DEM depressions is essential for reliable extraction of connected drainage networks from this type of data. The least-cost flow routing method implemented in GRASS GIS as the module r.watershed was redesigned to significantly improve its speed, functionality, and memory requirements and make it an efficient tool for stream mapping and watershed analysis from large DEMs. To evaluate its handling of large depressions, typical for remote sensing derived DEMs, three different methods were compared: traditional sink filling, impact reduction approach, and least-cost path search. The comparison was performed using the Shuttle Radar Topographic Mission (SRTM) and Interferometric Synthetic Aperture Radar for Elevation (IFSARE) datasets covering central Panama at 90 m and 10 m resolutions, respectively. The accuracy assessment was based on ground control points acquired by GPS and reference points digitized from Landsat imagery along segments of selected Panamanian rivers. The results demonstrate that the new implementation of the least-cost path method is significantly faster than the original version, can cope with massive datasets, and provides the most accurate results in terms of stream locations validated against reference points.
                    }, number={2}, journal={HYDROLOGY AND EARTH SYSTEM SCIENCES}, author={Metz, M. and Mitasova, H. and Harmon, R. S.}, year={2011}, pages={667–678} }
 @article{starek_mitasova_hardin_weaver_overton_harmon_2011, title={Modeling and analysis of landscape evolution using airborne, terrestrial, and laboratory laser scanning}, volume={7}, ISSN={["1553-040X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84858779393&partnerID=MN8TOARS}, DOI={10.1130/ges00699.1}, abstractNote={Current laser scanning (Lidar, light detection and ranging) technologies span a wide range of survey extent and resolutions, from regional airborne Lidar mapping and terrestrial Lidar field surveys to laboratory systems utilizing indoor three-dimensional (3D) laser scanners. Proliferation in Lidar technology and data collection enables new approaches for monitoring and analysis of landscape evolution. For example, repeat Lidar surveys that generate a time series of point cloud data provide an opportunity to transition from traditional, static representations of topography to terrain abstraction as a 3D dynamic layer. Three case studies are presented to illustrate novel techniques for landscape evolution analysis based on time series of Lidar data: (1) application of multiyear airborne Lidar surveys to a study of a dynamic coastal region, where the change is driven by eolian sediment transport, wave-induced beach erosion, and human intervention; (2) monitoring of vegetation growth and the impact of landscape structure on overland flow in an agricultural field using terrestrial laser scanning; and (3) investigation of landscape design impacts on overland water flow and other physical processes using a tangible geospatial modeling system. The presented studies demonstrate new insights into landscape evolution in different environments that can be gained from Lidar scanning spanning 1.0–0.001 m resolutions with geographic information system analysis capabilities.}, number={6}, journal={GEOSPHERE}, author={Starek, Michael J. and Mitasova, Helena and Hardin, Eric and Weaver, Katherine and Overton, Margery and Harmon, Russell S.}, year={2011}, month={Dec}, pages={1340–1356} }
 @article{barton_ullah_mitasova_2010, title={COMPUTATIONAL MODELING AND NEOLITHIC SOCIOECOLOGICAL DYNAMICS: A CASE STUDY FROM SOUTHWEST ASIA}, volume={75}, ISSN={["2325-5064"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77951558064&partnerID=MN8TOARS}, DOI={10.7183/0002-7316.75.2.364}, abstractNote={Archaeology has an opportunity to offer major contributions to our understanding of the long-term interactions of humans and the environment. To do so, we must elucidate dynamic socioecological processes that generally operate at regional scales. However, the archaeological record is sparse, discontinuous, and static. Recent advances in computational modeling provide the potential for creating experimental laboratories where dynamic processes can be simulated and their results compared against the archaeological record. Coupling computational modeling with the empirical record in this way can increase the rigor of our explanations while making more transparent the concepts on which they are based. We offer an example of such an experimental laboratory to study the long-term effects of varying landuse practices by subsistence farmers on landscapes, and compare the results with the Levantine Neolithic archaeological record. Different combinations of intensive and shifting cultivation, ovicaprid grazing, and settlement size are modeled for the Wadi Ziqlab drainage of northern Jordan. The results offer insight into conditions under which previously successful (and sustainable) landuse practices can pass an imperceptible threshold and lead to undesirable landscape consequences. This may also help explain long-term social, economic, and settlement changes in the Neolithic of Southwest Asia.}, number={2}, journal={AMERICAN ANTIQUITY}, author={Barton, C. Michael and Ullah, Isaac and Mitasova, Helena}, year={2010}, month={Apr}, pages={364–386} }
 @article{kennedy_murdoch_genereux_corbett_stone_pham_mitasova_2010, title={Comparison of Darcian flux calculations and seepage meter measurements in a sandy streambed in North Carolina, United States}, volume={46}, ISSN={["0043-1397"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77956498672&partnerID=MN8TOARS}, DOI={10.1029/2009wr008342}, abstractNote={We compared two methods for estimating groundwater flux into a stream reach: seepage meters and Darcian flux calculations. Both methods were applied at the same 53 points on the streambed of a 62.5‐m‐long reach of West Bear Creek in the coastal plain of North Carolina. At each point, a seepage meter was used to measure groundwater flux, vmeter, and several minutes later the streambed hydraulic conductivity (K) and hydraulic head gradient (J) were measured. We compared the 53 paired point values of groundwater flux from each method (vmeter and vdarcy = KJ), the integrated volumetric groundwater flux to the stream reach from each method (Qdarcy and Qmeter), and the spatial distributions of vdarcy and vmeter on the streambed. Values of Qmeter (268 m3/d) and mean vmeter (0.66 m/d) were each about 0.70 × the corresponding Darcian flux quantities (Qdarcy = 375 m3/d and mean vdarcy = 0.92 m/d). Despite their differences, the two methods gave the same direction of groundwater flow (into the stream) at all 53 points, a result not found in all previous comparison studies and thus not to be taken for granted. Also, vdarcy and vmeter had similar spatial distributions on the streambed. The ratio vmeter/vdarcy = 0.70 is within the range of 0.3–7 from previous studies and is closer to 1 than in previous studies. The differences between the two methods are probably in part due to random measurement error and to the spatial scales for the Darcy and seepage meter measurements being of a slightly different size and offset several centimeters from each other on the heterogeneous streambed, but these effects are unlikely to produce the observed consistent bias. The mean bias between the methods (ratio of 0.70) may be related to gas bubbles in the streambed pore spaces (e.g., collection of gas bubbles in the seepage meters lowering vmeter and loss of gas from the streambed upon seepage meter removal or permeameter insertion increasing the subsequent vdarcy measurement).}, number={9}, journal={WATER RESOURCES RESEARCH}, author={Kennedy, Casey D. and Murdoch, Lawrence C. and Genereux, David P. and Corbett, D. Reide and Stone, Katie and Pham, Phung and Mitasova, Helena}, year={2010}, month={Sep} }
 @inproceedings{kurum_edge_mitasova_overton_2010, title={Effects of coastal landform changes on storm surge along the hatteras island breach area}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84864486951&partnerID=MN8TOARS}, booktitle={Proceedings of the Coastal Engineering Conference}, author={Kurum, M.O. and Edge, B. and Mitasova, H. and Overton, M.}, year={2010} }
 @inproceedings{harmon_lyons_goldsmith_carey_welch_welch_forizs_long_mitasova_2010, title={Geochemistry of rivers in Panama}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84860171821&partnerID=MN8TOARS}, booktitle={Water-Rock Interaction - Proceedings of the 13th International Conference on Water-Rock Interaction, WRI-13}, author={Harmon, R.S. and Lyons, W.B. and Goldsmith, S.T. and Carey, A. and Welch, S. and Welch, K. and Forizs, I. and Long, D. and Mitasova, H.}, year={2010}, pages={253–256} }
 @inbook{harmon_lyons_goldsmith_carey_welch_welch_forizs_long_mitasova_2010, title={Geochemistry of rivers in Panama}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85055179064&partnerID=MN8TOARS}, booktitle={Water-Rock Interaction}, author={Harmon, R.S. and Lyons, W.B. and Goldsmith, S.T. and Carey, A. and Welch, S. and Welch, K. and Forizs, I. and Long, D. and Mitasova, H.}, year={2010}, pages={253–256} }
 @article{mitasova_hardin_overton_kurum_2010, title={Geospatial analysis of vulnerable beach-foredune systems from decadal time series of lidar data}, volume={14}, ISSN={1400-0350 1874-7841}, url={http://dx.doi.org/10.1007/s11852-010-0088-1}, DOI={10.1007/s11852-010-0088-1}, number={3}, journal={Journal of Coastal Conservation}, publisher={Springer Science and Business Media LLC}, author={Mitasova, Helena and Hardin, Eric and Overton, Margery F. and Kurum, Mustafa Onur}, year={2010}, month={Jan}, pages={161–172} }
 @article{tateosian_mitasova_harmon_fogleman_weaver_harmon_2010, title={TanGeoMS: Tangible Geospatial Modeling System}, volume={16}, ISSN={["1941-0506"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-78149238565&partnerID=MN8TOARS}, DOI={10.1109/tvcg.2010.202}, abstractNote={We present TanGeoMS, a tangible geospatial modeling visualization system that couples a laser scanner, projector, and a flexible physical three-dimensional model with a standard geospatial information system (GIS) to create a tangible user interface for terrain data. TanGeoMS projects an image of real-world data onto a physical terrain model. Users can alter the topography of the model by modifying the clay surface or placing additional objects on the surface. The modified model is captured by an overhead laser scanner then imported into a GIS for analysis and simulation of real-world processes. The results are projected back onto the surface of the model providing feedback on the impact of the modifications on terrain parameters and simulated processes. Interaction with a physical model is highly intuitive, allowing users to base initial design decisions on geospatial data, test the impact of these decisions in GIS simulations, and use the feedback to improve their design. We demonstrate the system on three applications: investigating runoff management within a watershed, assessing the impact of storm surge on barrier islands, and exploring landscape rehabilitation in military training areas.}, number={6}, journal={IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS}, author={Tateosian, Laura G. and Mitasova, Helena and Harmon, Brendan A. and Fogleman, Brent and Weaver, Katherine and Harmon, Russel S.}, year={2010}, pages={1605–1612} }
 @article{harmon_lyons_long_ogden_mitasova_gardner_welch_witherow_2009, title={Geochemistry of four tropical montane watersheds, Central Panama}, volume={24}, ISSN={["0883-2927"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-62849118013&partnerID=MN8TOARS}, DOI={10.1016/j.apgeochem.2008.12.014}, abstractNote={The major element chemistry was determined for surface waters from four watersheds in Central Panama during the 2005 dry season to ascertain geochemical patterns resulting from differing geology and human influences as well to estimate chemical denudation rates for this montane region of tropical rain forest. The Upper Rio Chagres (580 km2), Rio Pequini (281 km2) and Rio Cuango (175 km2) watersheds are formed on a geologically mixed terrain that consists of strongly hydrothermally altered andesite and volumetrically subordinate mafic-intermediate volcanic rocks and felsic intrusive lithologies, whereas the Rio Pacora watershed (374 km2) is developed largely on gabbroic and dioritic lithologies. The headwater areas of all four river basins lie in pristine tropical rainforest, with the Rio Cuango, Rio Pequini and Rio Pacora subject to varying degrees of different land uses in their middle to lower reaches. Values of pH for the four watersheds are near neutral to slightly alkaline (7.0–8.5), DO saturation is high (typically >90%) and dissolved solute contents of the rivers and tributary streams are low (SPC = 130 ± 31 μS/cm), documenting the overall pristine quality of the waters in all four basins. Cluster analysis, supported by a comparison of elemental variations, indicates a broad geochemical similarity of rivers and streams in the four watersheds, but also reveals subtle differences that can be attributed to lithologic control rather than anthropogenic influences. Low-order streams in the Pacora watershed have distinctly higher TDS values plus silica and Ca2+ concentrations than those forming in the mixed lithology terrain. Streams and rivers developed on mafic terrain are also slightly more enriched in total dissolved cations (TZ+) and HCO3-, relative to silica, than streams and rivers developed in the mixed lithology terrain. Potassium concentrations are uniformly low, and like Mg2+ and Na+, are similar in both terrains. Calcium/Mg ratios for all watersheds are lower than the world river average, indicating the importance of the weathering of Mg-rich minerals. The Ca/Na, HCO3/Na and Mg/Na ratios for the Rio Pacora streams and rivers fall within the mid-range of what has been observed globally for other streams/rivers draining mafic rocks. The chemical weathering rate calculated is 108 tons/km2/a, which is about 40% of the physical denudation rate for the Upper Rio Chagres watershed of 275–289 tons/km2/a. The results of this study document that both chemical and physical erosion rates within tropical montane watersheds in central Panama are significant in a global context.}, number={4}, journal={APPLIED GEOCHEMISTRY}, author={Harmon, Russell S. and Lyons, W. Berry and Long, David T. and Ogden, Fred L. and Mitasova, Helena and Gardner, Christopher B. and Welch, Kathleen A. and Witherow, Rebecca A.}, year={2009}, month={Apr}, pages={624–640} }
 @book{hofierka_mitásová_neteler_2009, title={Geomorphometry in GRASS GIS}, volume={33}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77955792959&partnerID=MN8TOARS}, DOI={10.1016/S0166-2481(08)00017-2}, abstractNote={Geographic Resources Analysis Support System (GRASS) is a general-purpose geographic information system (GIS) for the management, processing, analysis, modeling, and visualization of many types of georeferenced data. This chapter is based on GRASS 6.2 version available for all commonly used operating systems. It includes 2D raster and 3D voxel data support, a new topological 2D/3D vector engine and capabilities for vector network analysis. Attributes are managed in a SQL-based DBMS. Advances in mapping technologies, especially the rapid evolution of airborne and ground-based laser scanning, as well as satellite and airborne radar interferometry are bringing significant changes to geomorphic analysis. The point densities exceed the level of detail required for most applications and digital elevation models (DEMs) with resolutions of 3 m and better are becoming common even for large areas. The high mapping efficiency makes repeated mapping at relatively short time intervals feasible, resulting in multi-temporal DEMs. These developments require new concepts and approaches in geomorphometry. In response, GRASS modules are being further enhanced to accommodate very large data sets produced by the new mapping technologies; new tools are added for efficient handling of very dense elevation or bathymetry data, hierarchical watershed analysis and quantification of land-surface change.}, number={C}, journal={Developments in Soil Science}, author={Hofierka, J. and Mitásová, H. and Neteler, M.}, year={2009}, pages={387–410} }
 @inproceedings{overton_mitasova_recalde_2009, title={Geospatial time series analysis of volumetric change}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84873813560&partnerID=MN8TOARS}, booktitle={Proceedings of the Coastal Engineering Conference}, author={Overton, M. and Mitasova, H. and Recalde, J.J.}, year={2009}, pages={2099–2109} }
 @inproceedings{mitasova_hardin_overton_harmon_2009, title={New spatial measures of terrain dynamics derived from time series of lidar data}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-74349107746&partnerID=MN8TOARS}, DOI={10.1109/GEOINFORMATICS.2009.5293539}, abstractNote={We anticipate that multiyear lidar surveys, currently focused on vulnerable coastal areas, will soon become a common resource for monitoring and analysis of various aspects of regional terrain change. We propose raster based measures for mapping and quantification of discrete and continuous terrain changes by introducing novel concepts, such as core and envelope surfaces, contour evolution band, and evolution regression slope map that can provide insights into the spatial aspects of terrain dynamics and changes in structures. The methodology is applied to a section of North Carolina coast where multiyear time series of lidar data is already available. Dynamics of bare dune and beach systems, changes in structures and vegetation growth are mapped and quantified to evaluate the proposed approach.}, booktitle={2009 17th International Conference on Geoinformatics, Geoinformatics 2009}, author={Mitasova, H. and Hardin, E. and Overton, M. and Harmon, R.S.}, year={2009} }
 @article{mitasova_overton_recalde_bernstein_freeman_2009, title={Raster-Based Analysis of Coastal Terrain Dynamics from Multitemporal Lidar Data}, volume={25}, ISSN={["1551-5036"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-66449138133&partnerID=MN8TOARS}, DOI={10.2112/07-0976.1}, abstractNote={Abstract Multitemporal sets of lidar data provide a unique opportunity to analyze and quantify changes in topography in rapidly evolving landscapes. Methodology for geospatial analyses of lidar data time series was developed to investigate patterns of coastal terrain evolution, including the beach and dune systems. The diverse lidar-point data density, noise, and systematic errors were first quantified, and the results were used to compute a consistent series of high-resolution digital elevation models using spline-based approximation with optimized parameters. Raster-based statistical analysis was applied to the elevation-model time series to derive maps representing multiyear trends in spatial patterns of elevation change, to quantify dynamics at each cell using standard deviation maps, and to extract the core surface below which the elevation has never decreased. The methodology was applied to a North Carolina barrier island that was mapped by a sequence of 13 lidar surveys during the past decade, using several different lidar systems. Assessment of vertical differences between the lidar data sets using stable structures such as a road, was shown to be essential for correct quantification of coastal terrain change and its pattern. The analysis revealed the highly dynamic nature of foredunes, the trend toward inland sand transport, and the impact of anthropogenic sand disposal on that trend.}, number={2}, journal={JOURNAL OF COASTAL RESEARCH}, author={Mitasova, Helena and Overton, Margery F. and Recalde, Juan Jose and Bernstein, David J. and Freeman, Christopher W.}, year={2009}, month={Mar}, pages={507–514} }
 @article{kennedy_genereux_corbett_mitasova_2009, title={Relationships among groundwater age, denitrification, and the coupled groundwater and nitrogen fluxes through a streambed}, volume={45}, ISSN={["1944-7973"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-72149099351&partnerID=MN8TOARS}, DOI={10.1029/2008wr007400}, abstractNote={The relationships among coupled groundwater and nitrogen (N) fluxes, groundwater age, and denitrification were examined for a section of West Bear Creek, an agricultural stream in the coastal plain of North Carolina, United States. Simultaneous streambed measurements of hydraulic conductivity (K) and hydraulic head gradient (J) and the concentrations of NO3− ([NO3−]), dissolved gases, and chlorofluorocarbons in groundwater were interpolated, mapped, and (for water flux v = KJ and nitrate flux fNO3 = v[NO3−]) integrated over the streambed area. Nitrate and dissolved organic N accounted for 92 and 8% of N flux through the streambed, respectively. Streambed maps show a band of greater groundwater age, and lower [NO3−] and fNO3, running through the center of most of the study reach. Nitrate flux (fNO3) exhibits this “center‐low” pattern even though one of its controlling factors, groundwater flux (v), has on average the opposite “center‐high” pattern. An inverse relationship between [NO3−] and age is indicative of fertilizer as the primary source of groundwater NO3−. Denitrification reduced mean fNO3 by ∼50%, from 370 mmol m−2 d−1 (what it would have been in the absence of denitrification) to 173 mmol m−2 d−1 (what it actually was). Measurement of both groundwater age and v made possible a new method for estimating flow‐weighted mean groundwater age (τFWM), an important aquifer hydraulic characteristic related to groundwater storage and recharge rate. This method gives τFWM = 30 years, which, along with the overall distribution of groundwater ages, suggests the possibility of a significant time lag between changes in N fertilizer application rates and NO3− flux from groundwater to West Bear Creek. Differences in streambed groundwater chemistry between the left and right sides of the streambed suggest differences in agricultural practices on opposite sides of the stream.}, number={9}, journal={WATER RESOURCES RESEARCH}, author={Kennedy, Casey D. and Genereux, David P. and Corbett, D. Reide and Mitasova, Helena}, year={2009}, month={Sep} }
 @article{kennedy_genereux_corbett_mitasova_2009, title={Spatial and temporal dynamics of coupled groundwater and nitrogen fluxes through a streambed in an agricultural watershed}, volume={45}, ISSN={["0043-1397"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-72149089873&partnerID=MN8TOARS}, DOI={10.1029/2008wr007397}, abstractNote={This paper presents results on the spatiotemporal dynamics of the coupled water flux (v) and nitrogen fluxes (fN = v[N], where [N] is the concentration of a dissolved N species) through a streambed in an agricultural watershed in North Carolina. Physical and chemical variables were measured at numerous points in the streambed of a 0.26‐km reach: hydraulic conductivity (K) and head gradient (J) and the concentrations of NO3− and other N species in streambed groundwater, from which water flux (v = KJ) and N fluxes (e.g., fNO3 = v[NO3−]) through the streambed were computed, mapped, and integrated in space. The result was a novel set of streambed maps of the linked variables (K, J, v, and N concentrations and fluxes), showing their spatial variability and how it changed over a year (on the basis of seven bimonthly sets of maps). Mean fNO3 during the study year was 154 mmol m−2 d−1; this NO3− flux, together with that of dissolved organic nitrogen (fDON = 17 mmol m−2 d−1), accounted for >99% of the total dissolved N flux through the streambed. Repeat measurements at the same locations on the streambed show significant temporal variability in fNO3, controlled largely by changes in v rather than changes in [NO3−]. One of the clearest and most persistent aspects of spatial variability was lateral variability across the channel from bank to bank. K and v values were greater in the center of the channel; this distribution of K (ultimately a reflection of sediment dynamics in the channel) apparently focuses groundwater discharge toward the center of the channel. The opposite pattern (low values in the center) was found for J, [NO3−], and (to a lesser extent) fNO3. Overall, fNO3 was characterized by localized zones of high and low values that changed in size and shape over time but remained in basically the same locations (the same was true of K, J, and [NO3−], though less so for v), with 70% of NO3− flux occurring through about 38% of the streambed area. Lateral distributions of the physical hydrologic attributes (K, J, and v) were highly symmetrical across the channel, while those of [NO3−] and fNO3 showed higher values on the left than on the right, likely a reflection of different N use on opposite sides of the stream. The streambed‐based approach taken here offers insights concerning the spatial and temporal dynamics of linked water and N fluxes through a streambed and their controls.}, number={9}, journal={WATER RESOURCES RESEARCH}, author={Kennedy, Casey D. and Genereux, David P. and Corbett, D. Reide and Mitasova, Helena}, year={2009}, month={Sep} }
 @article{pelletier_mitasova_harmon_overton_2009, title={The effects of interdune vegetation changes on eolian dune field evolution: a numerical-modeling case study at Jockey's Ridge, North Carolina, USA}, volume={34}, ISSN={["1096-9837"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-69749085481&partnerID=MN8TOARS}, DOI={10.1002/esp.1809}, abstractNote={Abstract}, number={9}, journal={EARTH SURFACE PROCESSES AND LANDFORMS}, author={Pelletier, Jon D. and Mitasova, Helena and Harmon, Russell S. and Overton, Margery}, year={2009}, month={Jul}, pages={1245–1254} }
 @book{jolma_ames_horning_mitasova_neteler_racicot_sutton_2008, title={Chapter Ten Free and Open Source Geospatial Tools for Environmental Modelling and Management}, volume={3}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-51449107965&partnerID=MN8TOARS}, DOI={10.1016/S1574-101X(08)00610-8}, abstractNote={Geospatial (geographical) software systems (GIS) are used for creating, viewing, managing, analysing and utilising geospatial data. Geospatial data can include socioeconomic, environmental, geophysical, and technical data about the Earth and societal infrastructure and it is pivotal in environmental modelling and management (EMM). Desktop, web-based, and embedded geospatial systems have become an essential part of EMM, providing pre- or post-processing of geospatial data, analysis and visualisation of results or a graphical user interface (GUI). Many local, regional, national, and international efforts are underway to create geospatial data infrastructures and tools for viewing and using geospatial data. When environmental attribute data is linked to these infrastructures, powerful tools for environmental management are instantly created. The growing culture of free/libre and open source software (FOSS) provides an alternative approach to software development for the field of GIS (FOSS4G). To provide an overview of FOSS4G for EMM, we analyse platforms, software stacks, and EMM workflows. In the FOSS world the barriers to interoperability are low and thus the software stack tends to be thicker than in the proprietary platform. The FOSS4G world thrives on the evolution of software stacks and platforms. We provide examples of software stacks built from current FOSS4G that support EMM workflows and highlight the advantages of FOSS4G solutions including opportunities to redistribute resulting modelling tools freely to end-users and to support general goals of openness and transparency with respect to modelling tools.}, journal={Developments in Integrated Environmental Assessment}, author={Jolma, A. and Ames, D.P. and Horning, N. and Mitasova, H. and Neteler, M. and Racicot, A. and Sutton, T.}, year={2008}, pages={163–180} }
 @article{kennedy_genereux_mitasova_corbett_leahy_2008, title={Effect of sampling density and design on estimation of streambed attributes}, volume={355}, ISSN={["1879-2707"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-43949128733&partnerID=MN8TOARS}, DOI={10.1016/j.jhydrol.2008.03.018}, abstractNote={Underlying questions that are central to field studies of the groundwater–surface water interaction are the extent of error in means and spatial distributions of streambed attributes such as groundwater seepage rate or solute flux, and the relation of this error to the number and location of point measurements. To investigate these questions, spatially intensive point measurements of five streambed attributes were made in two 63-m long stream reaches in the North Carolina Coastal Plain: hydraulic conductivity (K), hydraulic head gradient between groundwater and stream water (J), nitrate concentration in streambed groundwater (C), and groundwater seepage (v = KJ) and nitrate flux (f = vC) through the streambed. In all, 10 datasets (2 reaches, 5 attributes), each with 54 closely-spaced point values, were created (540-point values in all). For each dataset, subsets of 8- to 40-point values were selected from the 54 available to evaluate the effects of sampling density (the number of point values per reach, or per m2 of streambed) and sampling design (the relative number of point values from the right side, left side, and center of the channel) on the mean and the spatial field of the streambed attribute. Specifically, we evaluated the following as a function of sampling density and sampling design: (1) the likelihood of error in the reach-average value of each streambed attribute, (2) the average magnitude of error and distribution of error in the reach-average value of each attribute, (3) the magnitude of error in the prediction of point values of each attribute, and (4) the geometry of interpolated surfaces of two attributes (K and f). In all cases, “error” in a value or interpolated surface based on a subset of points was taken as a deviation from the corresponding result based on the full dataset of 54 points. The probability (p) that error did not occur increased with sampling density for each sampling design and attribute in both reaches, though the effect of “diminishing returns” was evident for sampling densities greater than ∼24 points per reach (roughly 0.05–0.06 points per m2 of streambed). Relative to sampling density, sampling design had little effect on values of p. Average error in streambed attributes was generally small (⩽10%) and less than the 95% confidence limits about the reach-average values of the attributes. The ability to estimate unknown point values by interpolation among other point values was poor using both 12- and 36-point subsets, though results suggest the 24 additional known point values (in going from 12 to 36) were helpful in one case in which there was some degree of autocorrelation between the additional known values and the values to be predicted in the interpolation. Visual inspection of 130 contour maps showed that those based on 36-point values were far more realistic in appearance than those based on 12-point values (where the standard for “realistic” appearance was the contour maps based on the full datasets of 54-point values).}, number={1-4}, journal={JOURNAL OF HYDROLOGY}, author={Kennedy, Casey D. and Genereux, David P. and Mitasova, Helena and Corbett, D. Reide and Leahy, Scott}, year={2008}, month={Jun}, pages={164–180} }
 @book{neteler_mitasova_2008, title={Open source GIS: A GRASS GIS approach}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84892062276&partnerID=MN8TOARS}, DOI={10.1007/978-0-387-68574-8}, abstractNote={With this third edition of Open Source GIS: A GRASS GIS Approach, we enter the new era of GRASS6, the first release that includes substantial new code developed by the International GRASS Development}, journal={Open Source GIS: A GRASS GIS Approach}, author={Neteler, M. and Mitasova, H.}, year={2008}, pages={1–406} }
 @article{genereux_leahy_mitasova_kennedy_corbett_2008, title={Spatial and temporal variability of streambed hydraulic conductivity in West Bear Creek, North Carolina, USA}, volume={358}, ISSN={["1879-2707"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-48849088675&partnerID=MN8TOARS}, DOI={10.1016/j.jhydrol.2008.06.017}, abstractNote={The hydraulic conductivity (K) of the streambed is an important variable influencing water and solute exchange between streams and surrounding groundwater systems. However, there are few detailed data on spatial variability in streambed K and almost none on temporal variability. The spatial and temporal variability of streambed K in a North Carolina stream were investigated with 487 field measurements of K over a 1-year period. Measurements were made bimonthly from December 2005 to December 2006 at 46 measurement locations in a 262.5 m reach (the “large reach”). To give a more detailed picture of spatial variability, closely-spaced one-time measurements were made in two 62.5 m reaches (the “small reaches”, one investigated in July 2006 and the other in August 2006) that were part of the large reach. Arithmetic mean K for the large reach was ∼16 m/day (range was 0.01 to 66 m/day). Neither K nor lnK was normally distributed, and K distributions appeared somewhat bimodal. There was significant spatial variability over horizontal length scales of a few m. Perhaps the clearest feature within this variability was the generally higher K in the center of the channel. This feature may be an important control on water and chemical fluxes through the streambed (e.g., other measurements show generally higher water seepage velocity, but lower porewater nitrate concentration, in the center of the streambed). Grain size analysis of streambed cores showed that layers of elevated fines (silt + clay) content were less common in the center of the channel (overall, the streambed was about 94% sand). Results also suggest a modest but discernable difference in average streambed K upstream and downstream of a small beaver dam: K was about 23% lower upstream, when the dam was present during the first few months of the study. This upstream/downstream difference in K disappeared after the dam collapsed, perhaps in response to re-mobilization of fine sediments or leaf matter that had accumulated in quiet waters ponded on the upstream side of the dam. Temporal variability was significant and followed a variety of different patterns at the 46 measurement locations in the large reach. Temperature data show that variation in streambed and groundwater temperature was not an important cause of the observed temporal variability in K. Measurements of changes in the elevation of the streambed surface suggest erosion and deposition played an important role in causing the observed temporal variability in streambed K (of which the change described above following collapse of the beaver dam was a special case), though other potentially time-varying factors (e.g., gas content, bioturbation, or biofilms in the streambed) were not explicitly addressed and cannot be ruled out as contributors to the temporal variability in streambed K. Temporal variability in streambed K merits additional study as a potentially important control on temporal variability in the magnitudes and spatial patterns of water and solute fluxes between groundwater and surface water. From the data available it seems appropriate to view streambed K as a dynamic attribute, variable in both space and time.}, number={3-4}, journal={JOURNAL OF HYDROLOGY}, author={Genereux, David P. and Leahy, Scott and Mitasova, Helena and Kennedy, Casey D. and Corbett, D. Reide}, year={2008}, month={Sep}, pages={332–353} }
 @article{moore_mclaughlin_mitasova_line_2007, title={Calibrating WEPP model parameters for erosion prediction on construction sites}, volume={50}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34347247693&partnerID=MN8TOARS}, DOI={10.13031/2013.22639}, abstractNote={Soil erosion on construction sites can be many times greater than on agricultural fields, yet there has been little modeling done for construction conditions. The objective of our study was to calibrate management and soil parameters in the agriculturally based model Water Erosion Prediction Project (WEPP) for construction and post-construction site conditions. Data from a 4 ha watershed at various stages of construction in Wake County, North Carolina, were used to compare model results with measured runoff volume and sediment yields. Model simulations were performed in GeoWEPP, a geospatial interface designed for WEPP that operates within ArcView GIS. Model parameters were adjusted from WEPP default parameters as supported by the literature and site observations. Predicted values were regressed against field data for Nash-Sutcliffe model efficiency (NSE), with NSE > 0.50 regarded as satisfactory performance. We were able to generate runoff and sediment yields comparable to observed values by replacing soil surface properties with subsoil properties, in conjunction with the cutslope management parameter file in WEPP. We found a similar agreement between predicted and observed values for stabilized conditions by increasing critical shear stress from 0.3 to 10 Pa for the soil input layer. In addition, changes to the model source code to reduce the lower limit of effective hydraulic conductivity (Kef) for impermeable surfaces resulted in improved runoff NSE, but consequently increased sediment yield on areas with higher Kef values. WEPP has great potential for modeling applications on construction sites; however, more validation studies are needed to confirm and expand upon our findings.}, number={2}, journal={Transactions of the ASABE}, author={Moore, A.D. and McLaughlin, R.A. and Mitasova, H. and Line, D.E.}, year={2007}, pages={507–516} }
 @article{kennedy_genereux_corbett_mitasova_2007, title={Design of a light-oil piezomanometer for measurement of hydraulic head differences and collection of groundwater samples}, volume={43}, ISSN={["1944-7973"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-35848960791&partnerID=MN8TOARS}, DOI={10.1029/2007wr005904}, abstractNote={This paper describes a device (“piezomanometer”) that combines three components (an oil‐water manometer, a pushable screened PVC probe, and a system for groundwater sample collection) into a single inexpensive ($130), easily built, reliable tool for rapid collection of shallow groundwater from a streambed or lake bed and accurate measurement of even very small head differences between this groundwater and overlying surface water. The piezomanometer has been tested with excellent results both in the lab and in a stream shallow enough for wading; in principle, it could be adapted for use in deeper water where work is done from a dock, boat, or other platform. The problem of gas bubbles collecting in the groundwater line (a common drawback of field manometers) was nearly eliminated by use of a three‐way valve at a local elevation maximum in the groundwater line (gas bubbles in the groundwater line can be purged through this valve). Field application is illustrated here with data from a 2‐day study using four piezomanometers in a North Carolina stream.}, number={9}, journal={WATER RESOURCES RESEARCH}, author={Kennedy, Casey D. and Genereux, David P. and Corbett, D. Reide and Mitasova, Helena}, year={2007}, month={Sep} }
 @inproceedings{overton_mitasova_recalde_vanderbeke_2007, title={Morphological evolution of a shoreline on a decadal time scale}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84873027031&partnerID=MN8TOARS}, booktitle={Proceedings of the Coastal Engineering Conference}, author={Overton, M. and Mitasova, H. and Recalde, J.J. and Vanderbeke, N.}, year={2007}, pages={3851–3861} }
 @inproceedings{danner_m?lhave_yi_agarwal_arge_mitasova_2007, title={TerraStream: From elevation data to watershed hierarchies}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-79959666821&partnerID=MN8TOARS}, DOI={10.1145/1341012.1341049}, abstractNote={We consider the problem of extracting a river network and a watershed hierarchy from a terrain given as a set of irregularly spaced points. We describe TERRASTREAM, a "pipelined" solution that consists of four main stages: construction of a digital elevation model (DEM), hydrological conditioning, extraction of river networks, and construction of a watershed hierarchy. Our approach has several advantages over existing methods. First, we design and implement the pipeline so that each stage is scalable to massive data sets; a single non-scalable stage would create a bottleneck and limit overall scalability. Second, we develop the algorithms in a general framework so that they work for both TIN and grid DEMs. Furthermore, TERRASTREAM is flexible and allows users to choose from various models and parameters, yet our pipeline is designed to reduce (or eliminate) the need for manual intervention between stages.
 We have implemented TERRASTREAM and we present experimental results on real elevation point sets, which show that our approach handles massive multi-gigabyte terrain data sets. For example, we can process a data set containing over 300 million points---over 20GB of raw data---in under 26 hours, where most of the time (76%) is spent in the initial CPU-intensive DEM construction stage.}, booktitle={GIS: Proceedings of the ACM International Symposium on Advances in Geographic Information Systems}, author={Danner, A. and M?lhave, T. and Yi, K. and Agarwal, P.K. and Arge, L. and Mitasova, H.}, year={2007}, pages={212–219} }
 @article{wossink_mitasova_mclaughlin_2007, title={The cost effectiveness of standard and alternative sediment and turbidity control systems on construction sites in North Carolina}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-39749149040&partnerID=MN8TOARS}, number={360}, journal={Water Resources Research Institute News of the University of North Carolina}, author={Wossink, A. and Mitasova, H. and McLaughlin, R.}, year={2007} }
 @article{mitasova_mitas_ratti_ishii_alonso_harmon_2006, title={Real-time landscape model interaction using a tangible geospatial modeling environment}, volume={26}, ISSN={["1558-1756"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33746079196&partnerID=MN8TOARS}, DOI={10.1109/MCG.2006.87}, abstractNote={Emerging technologies that combine the flexibility of digital landscape representation with easy-to-interpret 3D physical models open new possibilities for user interaction with geospatial data. A prototype tangible geospatial modeling environment lets users interact with landscape analysis and simulations using a tangible physical model. We introduce a concept that builds upon previous independent tangible user interface (TUI) and terrain analysis research and aims at more intuitive collaborative interaction with digital landscape data.}, number={4}, journal={IEEE COMPUTER GRAPHICS AND APPLICATIONS}, author={Mitasova, Helena and Mitas, Lubos and Ratti, Carlo and Ishii, Hiroshi and Alonso, Jason and Harmon, Russell S.}, year={2006}, pages={55–63} }
 @inproceedings{mitasova_overton_harmon_berstein_2005, title={Assessing coastal hazards using recent 3D evolution of beach geomorphology based on lidar and RTK-GPS surveys}, volume={2005-January}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84950311360&partnerID=MN8TOARS}, DOI={10.1142/9789812701916-0255}, booktitle={Proceedings of the Coastal Engineering Conference}, author={Mitasova, H. and Overton, M.F. and Harmon, R.S. and Berstein, D.}, year={2005}, pages={3162–3172} }
 @article{mitasova_overton_harmon_2005, title={Geospatial analysis of a coastal sand dune field evolution: Jockey's Ridge, North Carolina}, volume={72}, ISSN={["1872-695X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-28744438601&partnerID=MN8TOARS}, DOI={10.1016/j.geomorph.2005.06.001}, abstractNote={Preservation and effective management of highly dynamic coastal features located in areas under development pressures requires in-depth understanding of their evolution. Modern geospatial technologies such as lidar, real time kinematic GPS, and three-dimensional GIS provide tools for efficient acquisition of high resolution data, geospatial analysis, feature extraction, and quantification of change. These techniques were applied to the Jockey's Ridge, North Carolina, the largest active dune field on the east coast of the United States, with the goal to quantify its deflation and rapid horizontal migration. Digitized contours, photogrammetric, lidar and GPS point data were used to compute a multitemporal elevation model of the dune field capturing its evolution for the period of 1974– 2004. In addition, peak elevation data were available for 1915 and 1953. Analysis revealed possible rapid growth of the dune complex between 1915–1953, followed by a slower rate of deflation that continues today. The main dune peak grew from 20.1 m in 1915 to 41.8 m in 1953 and has since eroded to 21.9 m in 2004. Two of the smaller peaks within the dune complex have recently gained elevation, approaching the current height of the main dune. Steady annual rate of main peak elevation loss since 1953 suggests that increase in the number of visitors after the park was established in 1974 had little effect on the rate of dune deflation. Horizontal dune migration of 3–6 m/yr in southerly direction has carried the sand out of the park boundaries and threatened several houses. As a result, the south dune section was removed and the sand was placed at the northern end of the park to serve as a potential source. Sand fencing has been an effective management strategy for both slowing the dune migration and forcing growth in dune elevation. Understanding the causes of the current movements can point to potential solutions and suggest new perspectives on management of the dune as a tourist attraction and as a recreation site, while preserving its unique geomorphic character and dynamic behavior.}, number={1-4}, journal={GEOMORPHOLOGY}, author={Mitasova, H and Overton, M and Harmon, RS}, year={2005}, month={Dec}, pages={204–221} }
 @article{mitasova_mitas_harmon_2005, title={Simultaneous spline approximation and topographic analysis for lidar elevation data in open-source GIS}, volume={2}, ISSN={["1558-0571"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-27744590597&partnerID=MN8TOARS}, DOI={10.1109/LGRS.2005.848533}, abstractNote={Application of a spline approximation method to computation and analysis of lidar-based digital elevation models is investigated to determine its accuracy and capability to create surfaces at different levels of detail. Quadtree segmentation that adapts to the spatial heterogeneity of data points makes the method feasible for large datasets. The results demonstrate the importance of smoothing for the surface accuracy and noise reduction. A tension parameter is effective for tuning the level of detail in the elevation surface. Simultaneous computation of topographic parameters is applied to extraction of sand dunes' features for assessment of dune migration and beach erosion.}, number={4}, journal={IEEE GEOSCIENCE AND REMOTE SENSING LETTERS}, author={Mitasova, H and Mitas, L and Harmon, RS}, year={2005}, month={Oct}, pages={375–379} }
 @article{warren_mitasova_hohmann_landsberger_iskander_ruzycki_senseman_2005, title={Validation of a 3-D enhancement of the Universal Soil Loss Equation for prediction of soil erosion and sediment deposition}, volume={64}, ISSN={["1872-6887"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-29244443457&partnerID=MN8TOARS}, DOI={10.1016/j.catena.2005.08.010}, abstractNote={A study was conducted on three U.S. military training areas to validate the Unit Stream Power Erosion and Deposition (USPED) model, a 3-dimensional enhancement to the Universal Soil Loss Equation (USLE). The USPED model differs from other USLE-based models in the manner in which it handles the influence of topography on the erosion process. As a result, the USPED model predicts both erosion and deposition, while most other USLE-based models are limited to predictions of erosion only. Erosion and deposition from a small watershed at Fort Hood, Texas, USA was quantified using 137Cs, a radioactive isotope found in soils around the world as a result of fallout from post-World War II nuclear testing. We compared 137Cs-derived erosion/deposition measurements with estimates derived from the USPED model and two applications of the USLE. Soil erosion and sediment deposition estimates generated by the USPED model were more accurate and less biased than results of the USLE applications. Both applications of the USLE consistently and significantly overestimated soil erosion; the USPED model did not. The USPED model was subsequently applied to Camp Guernsey, Wyoming, USA and Fort McCoy, Wisconsin, USA. Model estimates of soil erosion and sediment deposition were compared with field estimates of the same parameters. Based on 3 levels of soil erosion and 3 levels of sediment deposition, the model results agreed with field estimates 76 and 89% of the time at the two locations, respectively.}, number={2-3}, journal={CATENA}, author={Warren, SD and Mitasova, H and Hohmann, MG and Landsberger, S and Iskander, FY and Ruzycki, TS and Senseman, GM}, year={2005}, month={Dec}, pages={281–296} }
 @article{warren_hohmann_auerswald_mitasova_2004, title={An evaluation of methods to determine slope using digital elevation data}, volume={58}, ISSN={["1872-6887"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-8144226822&partnerID=MN8TOARS}, DOI={10.1016/j.catena.2004.05.001}, abstractNote={Variation in the computation of slope from digital elevation data can result in significantly different slope values and can, in turn, lead to widely varying estimates of environmental phenomena such as soil erosion that are highly dependent on slope. Ten methods of computing slope from distributed elevation data, utilizing capabilities inherent in five different geographic information systems (GIS), were compared with field measurements of slope. The methods were compared based on (1) overall estimation performance, (2) estimation accuracy, (3) estimation precision, and (4) independence of estimation errors and the magnitude of field measured slopes. A method utilizing a very high resolution digital elevation model (DEM) (1 m) produced slightly better estimates of slope than approaches utilizing somewhat lower resolution DEMs (2–5.2 m), and significantly better estimates than a method utilizing a 12.5 m DEM. The more accurate method was significantly biased, however, frequently underestimating actual slope. Methods that averaged or smoothed high resolution DEMs over larger areas also produced good estimates of slope, but these were somewhat less accurate in areas of shallow slopes. Methods utilizing differential geometry to compute percent slope from DEMs outperformed methods utilizing trigonometric functions. Errors in slope computation are exaggerated in soil erosion prediction models because erosion typically increases as a power function of slope.}, number={3}, journal={CATENA}, author={Warren, SD and Hohmann, MG and Auerswald, K and Mitasova, H}, year={2004}, month={Dec}, pages={215–233} }
 @book{neteler_mitasova_2004, title={Open source GIS: A GRASS GIS approach}, ISBN={1402080646}, publisher={Boston, MA: Kluwer Academic Publishers}, author={Neteler, M. and Mitasova, H.}, year={2004} }
 @book{mitasova_thaxton_hofierka_mclaughlin_moore_mitas_2004, title={Path sampling method for modeling overland water flow, sediment transport, and short term terrain evolution in Open Source GIS}, volume={55}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-80051576836&partnerID=MN8TOARS}, DOI={10.1016/S0167-5648(04)80159-X}, abstractNote={A path sampling method is proposed for solving the continuity equations describing mass flows over complex landscape surfaces. The modeled quantities are represented by an ensemble of sampling points which are evolved according to the corresponding Green function. The method enables incorporation of multi-scale/multi-process treatments. It has been used to develop simulation tools for overland shallow water flow and for sediment transport. The spatial pattern of sediment flow and net erosion/deposition is modeled using the closure relationship between sediment transport capacity and detachment developed for the USDA Water Erosion Prediction Project. The tools were recently implemented as modules in Open Source GRASS GIS. Their application is illustrated by the study of impact of land use and topography change on overland flow and sediment transport at North Carolina State University campus.}, number={PART 2}, journal={Developments in Water Science}, author={Mitasova, H. and Thaxton, C. and Hofierka, J. and McLaughlin, R. and Moore, A. and Mitas, L.}, year={2004}, pages={1479–1490} }
 @article{mitasova_drake_bernstein_harmon_2004, title={Quantifying rapid changes in coastal topography using modern mapping techniques and Geographic Information System}, volume={10}, ISSN={["1558-9161"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-1942466461&partnerID=MN8TOARS}, DOI={10.2113/10.1.1}, abstractNote={Innovative methodology based on a combination of real-time kinematic Global Positioning System (RTK-GPS), light detection and ranging (lidar), and open-source Geographic Information System (GIS) was developed to gain a better understanding of rapid changes in coastal topography. Improved spatial interpolation techniques were implemented to produce detailed topographic surfaces from lidar and RTK-GPS data. The methodology is demonstrated for two North Carolina areas: Jockey's Ridge State Park and Bald Head Island. The Jockey's Ridge study quantifies recent dune movement and identifies areas of elevation loss and rapid horizontal migration that threaten existing infrastructure. The Bald Head Island study examines pre- and post-nourishment beach evolution. The dynamics of beach topography, its geometric properties, and estimates of both eroded and deposited sand volumes were determined by combining lidar elevation data (1997–2000) with quarterly RTK-GPS measurements. Spatio-temporal analysis confirms the relative stability of the central ‘pivot point’ beach section and reveals that the beach changed its shape from convex west of the pivot point to concave east of the pivot point during the period of 1997 to 1998 and reversed shapes during year 2000. The pivot point also divides the beach into two sections that exhibit markedly different responses to nourishment. Although the entire length of nourished beach retreated, the analysis reveals that in the western section, all nourished sand off-shore was lost, whereas in the eastern section, significant sand volume was pushed up onto the beach, creating potential for recovery.}, number={1}, journal={ENVIRONMENTAL & ENGINEERING GEOSCIENCE}, author={Mitasova, H and Drake, TG and Bernstein, D and Harmon, RS}, year={2004}, month={Feb}, pages={1–11} }
 @inproceedings{thaxton_mitasova_mitas_mclaughlin_2004, title={Simulations of distributed watershed erosion, deposition, and terrain evolution using a path sampling Monte Carlo method}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-30044447669&partnerID=MN8TOARS}, booktitle={ASAE Annual International Meeting 2004}, author={Thaxton, C.S. and Mitasova, H. and Mitas, L. and McLaughlin, R.}, year={2004}, pages={2069–2082} }
 @article{mitasova_neteler_2003, title={Free general-purpose GIS: A geographic resources analysis support system}, volume={17}, ISBN={1566-9076}, number={11}, journal={GIM International}, author={Mitasova, H. and Neteler, M.}, year={2003}, pages={40} }
 @article{mitasova_neteler_2003, title={Free general-purpose GIS: A geographic resources analysis support system}, volume={17}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0242636615&partnerID=MN8TOARS}, number={11}, journal={GIM International}, author={Mitasova, H. and Neteler, M.}, year={2003}, pages={40–43} }
 @article{hofierka_mitasova_parajka_mitas_2002, title={Multivariate interpolation of precipitation using regularized spline with tension}, volume={6}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036204081&partnerID=MN8TOARS}, number={2}, journal={Transactions in GIS}, author={Hofierka, J. and Mitasova, H. and Parajka, J. and Mitas, L.}, year={2002}, pages={135–150} }
 @book{neteler_mitasova_2002, title={Open source GIS: A grass GIS approach}, ISBN={1402070888}, publisher={Boston: Kluwer Academic Publishers}, author={Neteler, M. and Mitasova, H.}, year={2002} }
 @article{mitas_mitasova_1998, title={Distributed soil erosion simulation for effective erosion prevention}, volume={34}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031911252&partnerID=MN8TOARS}, number={3}, journal={Water Resources Research}, author={Mitas, L. and Mitasova, H.}, year={1998}, pages={505–516} }
 @book{mitas_mitasova_1998, title={Multi-scale Green's function Monte Carlo approach to erosion modelling and its application to land-use optimization}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031767430&partnerID=MN8TOARS}, journal={Modelling soil erosion, sediment transport and closely related hydrological processes}, author={Mitas, L. and Mitasova, H.}, year={1998}, pages={81–90} }
 @article{mitas_mitasova_1998, title={Multi-scale Green's function Monte Carlo approach to erosion modelling and its application to land-use optimization}, volume={249}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-3342913036&partnerID=MN8TOARS}, journal={IAHS-AISH Publication}, author={Mitas, L. and Mitasova, H.}, year={1998}, pages={81–90} }
 @inproceedings{mitas_mitasova_1997, title={Green's function Monte Carlo approach to erosion modeling in complex terrain}, volume={1}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031343050&partnerID=MN8TOARS}, booktitle={Paper - American Society of Agricultural Engineers}, author={Mitas, Lubos and Mitasova, Helena}, year={1997} }
 @inproceedings{mitasova_brown_mitas_warren_1997, title={Multi-dimensional GIS environment for simulation and analysis of landscape processes}, volume={1}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031388938&partnerID=MN8TOARS}, booktitle={Paper - American Society of Agricultural Engineers}, author={Mitasova, Helena and Brown, William M. and Mitas, Lubos and Warren, Steven}, year={1997} }
 @article{mitasova_hofierka_zlocha_iverson_1997, title={Reply to Comment by Desmet and Govers}, volume={11}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0001704143&partnerID=MN8TOARS}, DOI={10.1080/136588197242220}, abstractNote={(1997). Reply to Comment by Desmet and Govers. International Journal of Geographical Information Science: Vol. 11, No. 6, pp. 611-618.}, number={6}, journal={International Journal of Geographical Information Science}, author={Mitasova, H. and Hofierka, J. and Zlocha, M. and Iverson, L.}, year={1997}, pages={611–618} }
 @article{mitas_brown_mitasova_1997, title={Role of dynamic cartography in simulations of landscape processes based on multivariate fields}, volume={23}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031454739&partnerID=MN8TOARS}, number={4}, journal={Computers and Geosciences}, author={Mitas, L. and Brown, W.M. and Mitasova, H.}, year={1997}, pages={437–446} }
 @article{mitasova_hofierka_zlocha_iverson_1996, title={Modelling topographic potential for erosion and deposition using GIS}, volume={10}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0030450685&partnerID=MN8TOARS}, number={5}, journal={International Journal of Geographical Information Systems}, author={Mitasova, H. and Hofierka, J. and Zlocha, M. and Iverson, L.R.}, year={1996}, pages={629–641} }
 @article{mitchell_pike_mitasova_1996, title={Using a geographic information system (GIS) for herbicide management}, volume={10}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0030478316&partnerID=MN8TOARS}, number={4}, journal={Weed Technology}, author={Mitchell, K.M. and Pike, D.R. and Mitasova, H.}, year={1996}, pages={856–864} }
 @article{mitasova_mitas_brown_gerdes_kosinovsky_baker_1995, title={Modelling spatially and temporally distributed phenomena: New methods and tools for GRASS GIS}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029502912&partnerID=MN8TOARS}, DOI={10.1080/02693799508902048}, abstractNote={Abstract The concept of GRASS (Geographic Resources Analysis Support System) as an open system has created a favourable environment for integration of process based modelling and GIS. To support this integration a new generation of tools is being developed in the following areas: (a) interpolation from multidimensional scattered point data, (b) analysis of surfaces and hypersurfaces, (c) modelling of spatial processes and, (d) 3D dynamic visualization. Examples of two applications are given-spatial and temporal modelling of erosion and deposition, and multivariate interpolation and visualization of nitrogen concentrations in the Chesapeake Bay.}, number={4}, journal={International Journal of Geographical Information Systems}, author={Mitasova, H. and Mitas, L. and Brown, W.M. and Gerdes, D.P. and Kosinovsky, R. and Baker, T.}, year={1995}, pages={433–446} }
 @article{mitá?ová_mitá?_1993, title={Interpolation by regularized spline with tension: I. Theory and implementation}, volume={25}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0027843999&partnerID=MN8TOARS}, DOI={10.1007/BF00893171}, number={6}, journal={Mathematical Geology}, author={Mitá?ová, H. and Mitá?, L.}, year={1993}, pages={641–655} }
 @article{mitá?ová_hofierka_1993, title={Interpolation by regularized spline with tension: II. Application to terrain modeling and surface geometry analysis}, volume={25}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0027844001&partnerID=MN8TOARS}, DOI={10.1007/BF00893172}, number={6}, journal={Mathematical Geology}, author={Mitá?ová, H. and Hofierka, J.}, year={1993}, pages={657–669} }
 @article{mitá?_mitá?ová_1988, title={General variational approach to the interpolation problem}, volume={16}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0000328364&partnerID=MN8TOARS}, DOI={10.1016/0898-1221(88)90255-6}, abstractNote={The Talmi and Gilat variational approach to the interpolation problem in arbitrary dimension is presented together with the corresponding physical model. The connection of this approach to some known spline methods is demonstrated and new interpolation functions are derived for one-, two- and three-dimensional cases. They are designed to be flexible through the use of meaningful parameters and to give good approximations of both the function itself and its derivatives as well.}, number={12}, journal={Computers and Mathematics with Applications}, author={Mitá?, L. and Mitá?ová, H.}, year={1988}, pages={983–992} }