Browsing by Author "Dymond, Randel L."
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- 3D Visualization of Highway Corridors: The I-77/81 Case Study near Wytheville, VAThota, Pramod Reddy (Virginia Tech, 2002-05-07)The application of Visualization and Simulation technologies to intuitively depict, analyze and execute transportation projects is gaining momentum, as advances in 3-Dimension (3D) Geographic Information Systems (GIS) technologies are rapidly progressing and there is an increased need for public acceptance of transportation projects. This thesis presents a visualization process framework that is applicable to highway corridor visualization, and the I-77/81 Relocation Study Visualization project is discussed along the lines of the visualization framework that has been developed. The changes in the roadway alignment and associated traffic volume and pattern changes will affect the town of Wytheville, both in terms of economy and community development. The goal of the project is to present these visualizations at public participation meetings. Visualizations that have been developed in 2D, 3D, 4D, and virtual reality, will be discussed along with their developmental life cycles and issues affecting their quality.
- Accuracy Assessment of the NLCD 2006 Impervious Surface for Roanoke and BlacksburgZhao, Suwen; Feng, Leyang; Shao, Yang; Dymond, Randel L. (2014)Impervious surface map products are important for the study of urbanization, urban heat island effects, watershed hydrology, water pollution, and ecosystem services in general. At the conterminous US scale, impervious surfaces are mapped for 2001 and 2006. The accuracy of the 2006 NLCD impervious surface, however, has not been thoroughly examined, especially for small and intermediate size cities (e.g., regional city). In this study, we selected two transects in two cities and visually interpreted aerial photo to develop impervious surface reference maps. We then compared percent impervious surface of the NLCD and aerial photo-interpreted reference maps. The comparison was conducted at 90m resolution to minimize the errors in image registration. Overall, we found that the 2006 NLCD impervious surface matched well with our reference data, although slight skewness at two extremes is present. The R² and RMSE statistics improved when the two datasets are compared at coarse aggregation levels (e.g. 180m).
- Analysis and Comparison of a Detailed Land Cover Dataset versus the National Land Cover Dataset (NLCD) in Blacksburg, VirginiaWhite, Claire McKenzie (Virginia Tech, 2011-12-06)While many studies have completed accuracy assessments on the National Land Cover Dataset (NLCD), little research has utilized a detailed digitized land cover dataset, like that available for the Town of Blacksburg, for this comparison. This study aims to evaluate the information available from a detailed land cover dataset and compare it with the National Land Cover Dataset (NLCD) at a localized scale. More specifically, it utilizes the detailed land cover dataset for the Town of Blacksburg to analyze the land cover distribution for varying land uses including single-family residential, multi-family residential, and non-residential. In addition, an application scenario assigns an area-weighted curve number to watersheds based on each land cover dataset. This study exhibits the importance of obtaining detailed land cover datasets for cities and towns. Furthermore, it shows the comprehensive information and subsequent quantifications that can be surmised from a detailed land cover dataset.
- An Analysis and Critique of DEM Creaion and 3-D Modeling Using Airborne LIDAR and Photogrammetric TechniquesGagné, Marissa Marlene (Virginia Tech, 2001-06-22)Three-dimensional (3D) visualization is rapidly becoming an important tool for many engineering projects. Accurate digital representations of terrain and ground features are extremely useful for efficient design, communication and data representation in projects involving land development, transportation planning, hydrologic analysis, environmental impact studies, and much more. Within the scope of terrain modeling lie a wide variety of techniques used to build digital elevation models (DEMs). Each approach has inherent problems and difficulties that can alter the accuracy and usability of the DEM produced. The main objectives of this study are to examine the various methods used for the creation of digital elevation models and make recommendations as to the appropriate techniques to use depending on specific project circumstances. Data sets generated using two of the methods, photogrammetry and LIDAR, are used to build digital terrain models in various software packages for an analysis of data usability and function. The key results of this research project are two DEMs of a real-world transportation study area and a set of conclusions and recommendations that give insight into the exact methods to be used on various projects. The paper ends with two short appendices, the first of which discusses several software packages and their effectiveness in DEM creation and 3-D modeling. The final appendix is a flow chart summarizing the recommendations for the seven DEM creation methods.
- An Analysis of Trends in U.S. Stormater Utility and Fee SystemsKea, Kandace (Virginia Tech, 2015-06-25)Many municipalities have established stormwater user fees (SUFs), commonly known as stormwater utilities, to raise revenue for stormwater management programs, however little is known about the trends among the fees currently in existence. This research observes trends in the establishment, type and magnitude of user fees by analyzing location, population density, home value, and establishment for a comprehensive national stormwater user fee database with data for 1,490 user fees. The Equivalent Residential Unit (ERU), a SUF that charges based on impervious area, was the most prevalent fee type in all NOAA Climate regions of the U.S. except the West and West North Central. The Tier system, a SUF that charges differently for properties by defined categories, was the second most prevalent in all regions except the East North Central and West North Central. The ERU was found in larger cities with high population densities whereas flat fees, SUFs that charge a single rate for all properties, were found in smaller towns. Higher home values led to higher monthly fees for 28% of the municipalities analyzed. The Residential Equivalence Factor (REF), a SUF that charges based on runoff produced, was popular in municipalities with higher home values and the flat fee was popular in those with lower home values. The number of SUFs established increased near Phase I MS4 permit and Phase II small MS4 permit deadlines.
- Analysis, Modeling, and Forecasting Of Urban FloodingBrendel, Conrad (Virginia Tech, 2020-04-08)As the world becomes more urbanized and heavy precipitation events increase in frequency and intensity, urban flooding is an emerging concern. Urban flooding is caused when heavy rainfall collects on the landscape, exceeding the capacity of drainage systems to effectively convey runoff. Unlike riverine and coastal flooding, urban flooding occurs frequently, and its risks and impacts are not restricted to areas within floodplains or near bodies of water. The objective of this dissertation is to improve our understanding of urban flooding and our capability to predict it through the development of tools and knowledge to assist with its analysis, modeling, and forecasting. To do this, three research objectives were fulfilled. First, the Stream Hydrology And Rainfall Knowledge System (SHARKS) app was developed to improve upon existing real-time hydrologic and meteorological data retrieval/visualization platforms through the integration of analysis tools to study the hydrologic processes influencing urban flooding. Next, the ability to simulate the hydrologic response of urban watersheds with large storm sewer networks was compared between the fully distributed Gridded Surface/Subsurface Hydrologic Analysis (GSSHA) model and the semi-distributed Storm Water Management Model (SWMM). Finally, the Probabilistic Urban Flash Flood Information Nexus (PUFFIN) application was created to help users evaluate the probability of urban flash flooding and to identify specific infrastructure components at risk through the integration of high-resolution quantitative precipitation forecasting, ensemble forecasting, and hydrologic and hydraulic modeling. The outcomes of this dissertation provide municipalities with tools and knowledge to assist them throughout the process of developing solutions to their site-specific urban flooding issues. Specifically, tools are provided to rapidly analyze and respond to rainfall and streamflow/depth information during intense rain events and to perform retrospective analysis of long-term hydrological processes. Evaluations are included to help guide the selection of hydrologic and hydraulic models for modeling urban flooding, and a new proactive paradigm of probabilistic flash flood guidance for urban areas is introduced. Finally, several potential directions for future work are recommended.
- Application of a Mobile Flux Lab for the Atmospheric Measurement of Emissions (FLAME)Moore, Tim Orland II (Virginia Tech, 2009-09-08)According to the World Health Organization, urban air pollution is a high public health priority due its linkage to cardio-pulmonary disease and association with increased mortality and morbidity (1, 2). Additionally, air pollution impacts climate change, visibility, and ecosystem health. The development of effective strategies for improving air quality requires accurate estimates of air pollutant emissions. In response to the need for new approaches to measuring emissions, we have designed a mobile Flux Lab for the Atmospheric Measurement of Emissions (FLAME) that applies a proven, science-based method known as eddy covariance for the direct quantification of anthropogenic emissions to the atmosphere. The mobile flux lab is a tool with novel, multifaceted abilities to assess air quality and improve the fidelity of emission inventories. Measurements of air pollutant concentrations in multiple locations at the neighborhood scale can provide much greater spatial resolution for population exposure assessments. The lab's mobility allows it to target specific sources, and plumes from these can be analyzed to determine emission factors. Through eddy covariance, the lab provides the new ability to directly measure emissions of a suite of air pollutants. We have deployed the FLAME to three different settings: a rural Appalachian town where coal transport is the dominant industry; schools in the medium-sized city of Roanoke, Virginia; and the large urban areas around Norfolk, Virginia, to measure neighborhood-scale emissions of air pollution. These areas routinely experience high ozone and particulate matter concentrations and include a diverse array of residential neighborhoods and industries. The FLAME is able to capture emissions from all ground-based sources, such as motor vehicles, rail and barge traffic, refuse fires and refueling stations, for which no direct measurement method has been available previously. Experiments focus on carbon dioxide (CO₂), the principal greenhouse gas responsible for climate change; nitrogen oxides (NOx), a key ingredient in ground-level ozone and acid rain; volatile organic compounds (VOCs), a second key ingredient in ozone and many of which are air toxics; and fine particulate matter (PM2.5), a cause of mortality, decreased visibility, and climate change. This research provides some of the first measurements of neighborhood-scale anthropogenic emissions of CO₂, NOx, VOCs and PM2.5 and as a result, the first opportunity to validate official emission inventories directly. The results indicate that a mobile eddy covariance system can be used successfully to measure fluxes of multiple pollutants in a variety of urban settings. With certain pollutants in certain locations, flux measurements confirmed inventories, but in others, they disagreed by factors of up to five, suggesting that parts of the inventory may be severely over- or underestimated. Over the scale of a few kilometers within a city, emissions were highly heterogeneous in both space and time. FLAME-based measurements also confirmed published emission factors from coal barges and showed that idling vehicles are the dominant source of emissions of air toxics around seven schools in southwest Virginia. Measurements from this study corroborate existing emission inventories of CO₂ and NOx and suggest that inventories of PM2.5 may be overestimated. Despite the tremendous spatial and temporal variability in emissions found in dense urban areas, CO₂ fluxes on average are very similar across the areas in this study and other urban areas in the developed world. Nevertheless, the high level of variability in spatial and temporal patterns of emissions presents a challenge to air quality modelers. The finding that emissions from idling vehicles at schools are likely responsible for creating hot spots of air toxics adds to the urgency of implementing no-idling and other rules to reduce the exposure of children to such pollutants. Ultimately, the results of this study can be used in combination with knowledge from existing emission inventories to improve the science and policies surrounding air pollution.
- Areal Modeling of Erosion for Environmental Nonpoint Applications (AMEENA)Al-Smadi, Mohammad Ahmed (Virginia Tech, 2007-08-10)Erosion and sediment delivery from upland areas to waterbodies is a major problem impacting water quality in the United States and elsewhere. Measures to reduce these impacts are either targeted at reducing erosion on-site or at reducing delivery of sediment to waterbodies. AMEENA (Areal Modeling of Erosion for Environmental Nonpoint Applications) is a spatially distributed model that estimates erosion and deposition on a watershed scale by predicting erosion and transport over the landscape surface. Erosion is predicted based on the Revised Universal Soil Loss Equation (RUSLE), and sediment transport capacity is estimated as a function of upslope flow volume, local gradient, and land use. Gross erosion is routed to edge-of-stream with a routing algorithm that iteratively compares available sediment with transport capacity on a cell by cell basis from ridge cells to stream cells. The model is implemented completely within a raster GIS to facilitate use of the model as a tool to readily evaluate impact of land use practices on sediment delivery to streams. AMEENA was validated using field data of net erosion and sediment deposition from three field studies. AMEENA predicted the spatial distribution of net erosion and deposition better than WaTEM/SEDEM which is a distributed parameter erosion model based on a similar modeling approach. AMEENA's suitability to simulate the impact of management practices such as filter strips and critical area planting was evaluated on plot (profile) scale and catchment scale simulations. Results of plot scale simulations were intuitive and the model proved more reasonable for these scenarios than did RUSLE2 and WEPP. The catchment scale study highlighted features of AMEENA that are not available in RUSLE2 and WEPP in terms of identifying erosion “hot spots” and the ability to utilize the explicit sediment flow path identification in locating best placement of off-site sediment control measures. Since AMEENA does not account for in-stream erosion processes, it is not suitable for simulating areas dominated by channel or gully erosion.
- Assessment of Mansionization and Residential Infill Development on Stormwater RunoffHekl, Meghan Louise (Virginia Tech, 2018-06-19)Residential infill development and the associated increases in impervious cover and stormwater runoff have the potential to overwhelm aging infrastructure causing erosion, flooding, and ecological degradation of waterways. The lack of greenfield sites available for new development around urban centers coupled with a desire for maintaining a traditional neighborhood aesthetic drives residential infill and replacement of existing smaller homes by significantly larger structures, minimizing open space available for stormwater mitigation. An analysis of residential infill development trends in Fairfax County was performed to characterize the effects of intensified development. Development patterns were identified and assessed using digitized impervious cover data extracted from aerial imagery of the study area for six selected years from 2002 to 2015. The average annual increase in percent impervious area was computed to be 0.3%. Redevelopment was found to be mainly occurring in areas zoned as lower-density residential. The spatial distribution of redevelopment showed trends of clustered increases as opposed to isolated events. The hydrologic analysis performed revealed that from 2002 to 2015, there was an 8,930 m3 (7.2 acre-ft) increase in stormwater runoff volume, 38% of which is contributed to by runoff generated from development that is considered exempted from regulation in Fairfax County. Additionally, there was a 28 kg/year (62 lb/year) increase in total phosphorus loads attributable to the change in impervious cover due to residential development throughout the study area. The results of this study provide a quantitative basis for municipalities to amend policies regulating residential development and its associated stormwater management.
- Assessment of Predictive Real-Time Control Retrofits on Stormwater Basin Performance in an Urban WatershedHonardoust, Dylan Russell (Virginia Tech, 2020-06-04)The potential real-time control (RTC) has to improve the performance of existing stormwater management systems is a topic of increasing interest as hydraulic and hydrologic modeling capabilities proliferate. The benefits of incorporating precipitation forecast data into a RTC algorithm to allow for prediction-based control of an urban watershed is explored using an EPA SWMM 5.1 watershed model. One reactive and two predictive RTC algorithms are simulated in various configurations across seven dry detention ponds located in the 162 hectare urbanized watershed. The hydraulic benefits they provide at the site and watershed outlet in regards to peak flow and the flow duration curve are compared to conventional, static control. The ponds retrofit with the novel predictive RTC algorithm had lower peak flows during 24-hour design storms more consistently than when retrofit with reactive RTC. The duration of erosive flows at the site level was decreased by the novel predictive RTC in most cases. Improvements at the watershed outlet depended on where RTC was applied as hydrograph compounding was observed during some RTC implementations.
- Bioretention Hydrologic Performance in an Urban Stormwater NetworkJames, Matthew Bruce (Virginia Tech, 2010-04-30)While many studies have evaluated the hydrologic effects of bioretention at the site level, few have investigated the role bioretention plays when distributed throughout a watershed. This study aims to assess bioretention's effects on an urbanized watershed using two modeled scenarios: one where runoff from many land uses was routed through the practice, and another in which only runoff from large impervious areas was routed. Peak flows, volumes, and lag times from these models were compared to the watershed's current and predeveloped conditions. Both scenarios provided reductions in peak flows with respect to existing conditions for modeled storm events, sometimes to levels below the predeveloped condition. Neither case was able to reduce volumes to predevelopment levels; the option to treat impervious areas had a negligible effect on runoff volume. Both cases were able to extend lag times from the existing development condition. Based on these results, bioretention appears to have the capability to improve watershed hydrologic characteristics. Furthermore, only treating impervious areas could be a viable alternative when funds or space are limiting factors.
- Bivariate Best First Searches to Process Category Based Queries in a Graph for Trip Planning Applications in TransportationLu, Qifeng (Virginia Tech, 2009-02-25)With the technological advancement in computer science, Geographic Information Science (GIScience), and transportation, more and more complex path finding queries including category based queries are proposed and studied across diverse disciplines. A category based query, such as Optimal Sequenced Routing (OSR) queries and Trip Planning Queries (TPQ), asks for a minimum-cost path that traverses a set of categories with or without a predefined order in a graph. Due to the extensive computing time required to process these complex queries in a large scale environment, efficient algorithms are highly desirable whenever processing time is a consideration. In Artificial Intelligence (AI), a best first search is an informed heuristic path finding algorithm that uses domain knowledge as heuristics to expedite the search process. Traditional best first searches are single-variate in terms of the number of variables to describe a state, and thus not appropriate to process these queries in a graph. In this dissertation, 1) two new types of category based queries, Category Sequence Traversal Query (CSTQ) and Optimal Sequence Traversal Query (OSTQ), are proposed; 2) the existing single-variate best first searches are extended to multivariate best first searches in terms of the state specified, and a class of new concepts--state graph, sub state graph, sub state graph space, local heuristic, local admissibility, local consistency, global heuristic, global admissibility, and global consistency--is introduced into best first searches; 3) two bivariate best first search algorithms, C* and O*, are developed to process CSTQ and OSTQ in a graph, respectively; 4) for each of C* and O*, theorems on optimality and optimal efficiency in a sub state graph space are developed and identified; 5) a family of algorithms including C*-P, C-Dijkstra, O*-MST, O*-SCDMST, O*- Dijkstra, and O*-Greedy is identified, and case studies are performed on path finding in transportation networks, and/or fully connected graphs, either directed or undirected; and 6) O*- SCDMST is adopted to efficiently retrieve optimal solutions for OSTQ using network distance metric in a large transportation network.
- A Comparison of Imperviousness Derived from a Detailed Land Cover Dataset (DLCD) versus the National Land Cover Dataset (NLCD) at Two Time PeriodsCooper, Brandon Elliott (Virginia Tech, 2016-09-01)To address accuracy concerns of the National Land Cover Dataset (NLCD), this case study compares impervious surface from the NLCD to a Detailed Land Cover Dataset (DLCD) for the Town of Blacksburg, Virginia over two time periods (2005/2006 and 2011) at spatial aggregation scales (fine to coarse) and scopes (site-specific to area-extent). When comparing the total impervious surface area, the NLCD overestimated the DLCD by appreciable amounts (12-27%) for the entire town and across all specified land use zones for both time periods examined. A binary pixel-wise accuracy assessment of impervious surface revealed that the NLCD performed well for all scopes except for the single family land use zone (user accuracy <40%). The spatial aggregation of pixels to 90-m led to improved agreement between the two datasets. Using the DLCD as a reference, an empirical normalization equation was successfully applied to the NLCD to further reduce overestimation and data skewness.
- Cost Trends and Estimates for Dam Rehabilitation in the Commonwealth of VirginiaBaron, Stefany A. (Virginia Tech, 2020-06-08)In recent years, the United States has seen a high demand for dam rehabilitation projects as most dam infrastructure has started to reach or exceed the expected life span of 50-70 years. Rehabilitation projects can be very expensive, however, and the funding options for dam owners are limited. To raise awareness, organizations such as ASDSO and the Virginia DCR release cost estimates every few years to encourage more investment in dam infrastructure. Unfortunately, many cost estimates have been made with limited data and outdated methodologies. This research collects a new sample of cost data for Virginia dam rehabilitation projects and uses it to assess key factors for cost estimating. Factors such as height, drainage area, hazard classification, and ownership type were used to make regression models that predict the cost of addressing Virginia's non-compliant dams. This study estimates that approximately $300 million is needed to address Virginia's 98 deficient high hazard, local government owned dams and that $122 million of that estimate is need for SWCD dams alone.
- Determining the Value of Pedestrian Surfaces in Suburban DCAyers, William Grove (Virginia Tech, 2014-07-01)Recent demographic studies suggest a shift in consumer preference away from auto-centric suburban housing to more walkable suburban communities. In response to these changes, efforts have been made to model the walkability of a location and determine its effect on the market value of both residential and commercial real estate. Existing walkability models have considered the importance of amenities and potential pedestrian routes, but have neglected to identify the importance of pedestrian surfaces such as sidewalks and trails as a proportion of the route traveled, and have typically modeled pedestrian movement using exclusively street or trail centerline data. The following paper uses a new walkability model to provide insight on the effect pedestrian surfaces along these amenity routes have on the market value of single family detached and semi-detached homes in Fairfax County, VA. It was found that increases in pedestrian surfaces along amenity routes had little to no effect on home value, but that 3.3%, 1.2 %, and 0.7 % price premiums existed for single family homes that had amenity paths of less than 1 mile to public transportation, public spaces, and recreational facilities, respectively. Price reductions of 3.0 % were discovered for homes that had amenity paths within 1 mile of retail locations.
- Developing an operational procedure to produce digitized route maps using GPS vehicle location dataPadmanabhan, Vijaybalaji (Virginia Tech, 2000-04-26)Advancements in Global Positioning System (GPS) technology now make GPS data collection for transportation studies and other transportation applications a reality. Base map for the application can be obtained by importing the road centerline map into GIS software like AutoCAD Map, or Arc/Info or MapixTM. However, such kinds of Road Centerline maps are not available for all places. Therefore, it may be necessary to collect the data using GPS units. This thesis details the use of GPS technology to produce route maps that can be used to predict arrival time of a bus. This application is particularly useful in rural areas, since the bus headway in a rural area is generally larger than that in an urban area. The information is normally communicated through various interfaces such as internet, cable TV, etc., based on the GPS bus location data. The objective of this thesis is to develop an operational procedure to obtain the digitized route map of any desired interval or link length and to examine the accuracy of the digitized map. The operational procedure involved data collection, data processing, algorithm development and coding to produce the digitized route maps. An algorithm was developed produce the digitized route map from the base map of the route, coded in MATLAB, and can be used to digitize the base map into any desired interval of distance. The accuracy comparison is made to determine the consistency between the digitized route map and the base map.
- Developing Digital Monitoring Protocols for Use in Volunteer Stream AssessmentAnderson, Jason (Virginia Tech, 2001-12-06)The traditional paper-based method of field data collection has always been a time-consuming and cumbersome process. Agency personnel in the field complete a standard evaluation form, which is then returned to the office and entered into a computer database for storage and analysis. Throughout this process, data can easily be lost or misinterpreted. As data requirements continue to expand, field data collection can quickly overwhelm a regulatory agency's manpower and resources, which only serves to exacerbate these problems. Recent technological developments can help agencies and organizations keep up with this growing demand and have begun to change the method of data collection and management. The overall goal of this study is to develop, demonstrate, and evaluate a digital protocol for the use of technology in a volunteer stream monitoring application and draw conclusions on its applicability as a more effective means of data collection in a wide variety of fields. The protocol includes digital evaluation forms and integrated help files for use in the field. The digital evaluation forms are based on paper evaluation forms developed by researchers conducting a stream corridor assessment of Stroubles Creek in Blacksburg, Virginia. The protocol was developed using available hardware and software. Collected data can be downloaded directly from a Personal Digital Assistant (PDA) and stored on a hard drive or system server. The data can then be input directly into a Geographic Information System (GIS) database to enhance the visualization and usefulness of the information. The GIS allows surveyors to view the relationships among the many factors affecting the stream, as well as preparing the data for advanced analysis. Two examples are provided: a field application of the protocol on streams currently listed for Total Maximum Daily Load (TMDL) development; and an environmental education setting in a Virginia elementary school. Conclusions drawn from these applications are also described.
- Development and Evaluation of the Online Watershed Learning System (OWLS)Brogan, Daniel S. (Virginia Tech, 2017-03-01)Cyberlearning has the ability to connect learners from diverse settings to educational resources regardless of the learners' proximities to traditional classroom environments. Prior research has shown that hybrid learning systems more effectively improve student learning than do either traditional or cyberlearning approaches used individually. The Online Watershed Learning System (OWLS) is an interactive cyberlearning system for use in hybrid education. It serves as the end user interface of the Learning Enhanced Watershed Assessment System (LEWAS), a watershed monitoring system for use in research and education. The LEWAS/OWLS has been integrated into 26 courses. Within the theoretical framework of situated learning, the OWLS uses data and imagery to situate users at the LEWAS site. The current research has the dual goals of developing the OWLS and evaluating its effectiveness within a hybrid learning environment as part of watershed monitoring education. Within goal 1, HTML5, CSS and JavaScript code (11,112 lines) were used to achieve platform independence, and student and faculty feedback suggests a hierarchy of cyberlearning interface features, where anywhere/anytime access is the most important class of features for these users followed by real-time data visualization, system background information and how-to-use information in descending order. For students at the community college freshmen, university senior and graduate levels, goal 2 investigated how much the OWLS increases student learning of environmental monitoring topics and motivates them to study these topics. For this goal, use of the LEWAS/OWLS increased learning and motivation for most students with the caveats that the these gains were not always statistically significant and that these gains may be caused by use of the LEWAS in general rather than by the OWLS component of it. Additional studies are needed to resolve these issues. Additionally, a pilot test of anonymous user tracking (11,231 page views) showed how it can be used to obtain general information about which groups of users are accessing a cyberlearning system, how they are accessing it, and how navigation through the system can be improved to better match user goals. The full results and their limitations are included along with areas for future work.
- Development and Evaluation of the Profile Synthesis Method for Approximate Floodplain RedelineationDickerson, Thomas Ashby (Virginia Tech, 2007-11-15)In the United States, the floodplain maps used in the administration of the National Flood Insurance Program are created and maintained by the Federal Emergency Management Agency. Currently, a nationwide map modernization program is underway to convert the existing paper floodplain maps into a digital format, while continuing to improve the maps and expand the scope of the studies. The flood zones depicted on these maps are developed through engineering studies, using a variety of accepted methods to model and predict flood-prone areas. These methods are classified as detailed, limited detailed, or approximate, corresponding to varying levels of expense and accuracy. Current flood map revision activities across the nation typically consist of developing new hydraulic models, or reusing existing hydraulic model results in conjunction with new, more detailed LiDAR terrain models. This research develops a profile synthesis method for redelineation of approximate flood boundaries, and evaluates the method's performance and usability. The profile synthesis method is shown to perform reliably on simple floodplain geometry, recreating a water surface profile based only on its floodplain boundaries. When applied to a real-world floodplain studied in a previous flood insurance study, the profile synthesis method is shown to perform adequately, with results comparable to an approximate hydraulic model developed in HEC-RAS. Methods similar to this profile synthesis method for reuse of existing approximate zone boundaries have not been widely documented or evaluated; nevertheless, methods such as this are believed to be common in the revision of approximate zone flood boundaries. As such, this work explores concepts which will be of interest to individuals actively involved in flood map revision and modernization.
- Development of a Spatial Decision Support System for Emergency Medical Service Facility SitingMuza, Matej (Virginia Tech, 2011-05-02)Improved strategic location of an Emergency Medical Service (EMS) facility can significantly increase EMS efficiency. Urban planners need to consider a location that satisfies multiple criteria in order to make an informed decision about a future EMS facility site. Apart from basic criteria such as parcel value and size, decision-makers need to consider area and population coverage from potential parcels. Geographic Information Systems (GIS) provide an adequate analysis environment for EMS facility siting as many considered criteria are of a spatial nature. However, urban planners making decisions about an EMS facility site often lack the necessary expertise to make full use of challenging GIS tools. In order to help urban planners in the analysis process, this research developed a Spatial Decision Support System (SDSS) for EMS facility siting. The system was developed in ESRI ArcGIS (9.3) using the Visual Basic for Applications (VBA) programming environment. The objective of the system was to integrate spatial data, analysis, and visualization in a single system to help users evaluate a facility siting problem. The system's performance was tested using data for the Town of Blacksburg, VA. In addition, the system was evaluated by local planners and GIS staff with experience in EMS facility siting. Planners agreed the system enables more comprehensive and straightforward use of GIS for EMS facility siting analysis than other available siting tools. Potential improvements include a simpler user interface, synthesis of geoprocessing techniques, reduction of analysis time through automation, and better decision-making by improved visualization of results.