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The Impact Of Varied Nominal Posting Density Lidar Data On Dem Accuracy Hydraulic Modeling And Flood Zone Delineation
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Book Synopsis The Impact of Varied Nominal Posting Density Lidar Data on DEM Accuracy, Hydraulic Modeling and Flood Zone Delineation by : George Thomas Raber
Download or read book The Impact of Varied Nominal Posting Density Lidar Data on DEM Accuracy, Hydraulic Modeling and Flood Zone Delineation written by George Thomas Raber and published by . This book was released on 2003 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Influence of Post-spacing Density of DEMS Derived from LIDAR on Flood Modeling by : Pierre Gueudet
Download or read book The Influence of Post-spacing Density of DEMS Derived from LIDAR on Flood Modeling written by Pierre Gueudet and published by . This book was released on 2004 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Assessing the Resolution Effects of Digital Elevation Models on Automated Floodplain Delineation by : Richard Charrier
Download or read book Assessing the Resolution Effects of Digital Elevation Models on Automated Floodplain Delineation written by Richard Charrier and published by . This book was released on 2009 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Automated floodplain modeling commonly requires Digital Elevation Models (DEMs) to represent the topography. As a raster representation of the Earth surface, changing a DEMs resolution (data cell size) has a profound impact on the floodplain delineation. Since 1995 DEM resolution has increased from 100- to 1-meter resolution. This thesis addresses how different DEM resolutions, and different DEM data sources, affect the outcome of modeled floodplain boundaries in the Camp Creek Watershed, a predominately agricultural watershed in Missouri. Two data sets are analyzed: a Light Detection and Ranging (LiDAR) terrain model re-sampled to 1-, 3-, 5-, 10-, 15-, and 30-meter resolutions and existing United States Geological Survey (USGS) 5-, 10-, and 30-meter DEMs. The floodplain delineation process includes hydrologic modeling, hydraulic modeling, and floodplain delineation. Each process includes various input parameters and outputs. Resultant stream networks, watershed boundaries, and floodplains are examined to evaluate the effects of different resolutions. Using 3- or 5- meter LiDAR DEMs produces data that agree with the 1-m data greater than the 90th percentile. The agreement also includes the 10-m DEM data when analyses remove the floodplain modeling cumulative discrepancy effects. Similar trends were not found when using the USGS counterparts; possibly due to the use of the same underlying source material to create the DEMs. When removing the cumulative distortion effect of resolution on the entire modeling process, LiDAR DEM floodplains displayed a 1-4% increase in goodness of fit. Analyzing the results of two separate hydraulic models (HEC-RAS and CARES) finds little difference between their calculated flood surface elevations. Additionally, the thesis analyzes the data storage needs and processing time for modeling different resolutions, finding substantial savings in both as the underlying DEM resolution is decreased. The thesis begins to analyze how models are affected by input variables but many additional studies are needed. Further study of these variables is needed to determine if a single most appropriate model and DEM resolution exists, or what combination of models are appropriate for various types of automated floodplain modeling.
Book Synopsis Assessing Accuracy in Varying LIDAR Data Point Densities in Digital Elevation Maps by :
Download or read book Assessing Accuracy in Varying LIDAR Data Point Densities in Digital Elevation Maps written by and published by . This book was released on 2008 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses the production of Digital Elevation Maps (DEM) using varying density of data points from a Lidar (Laser or Light Detection And Ranging) collection. Additionally, this thesis contains information on the multiple space missions that use laser altimetry or Lidar to gather data about planet earth, the moon, asteroids, Mars and Mercury. The thesis covers the accuracy of different amounts of data used when generating a DEM in Quick Terrain Modeler software package and the ILAP Bare Earth Extraction Plug-In and discusses the error analysis when comparing the different DEMs built by randomly selecting 90%, 66%, 50%, 30%, 10%, 5%, 3%, 1%, 0.5%, 0.3%, 0.05%, 0.03% and 0.01% of the data from an airborne Lidar collection from Honduras in 2008. Analyzing surface DEMs created in QTM, the results of the point reduction experiment indicate that a collection cloud point density of 60,000 points per square kilometer are required for an accurate surface DEM in this environment.
Book Synopsis Point Density Effects on Digital Elevation Models Generated from LiDAR Data by :
Download or read book Point Density Effects on Digital Elevation Models Generated from LiDAR Data written by and published by . This book was released on 2009 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of Airborne LiDAR Systems (ALS) to obtain topographical information of the earth's surface and generate Digital Elevation Models (DEMs) has grown extensively in the field of Remote Sensing. Selected areas of point cloud LiDAR data collected from Honduras in 2008 was used to produce DEMs with varying densities to show the effects of lower resolution LiDAR data. An IDL code was utilized to reduce the selected LiDAR point cloud data to 90%, 66%, 50%, 30%, 10%, 5%, 3%, 1%, 0.5%, 0.3%, 0.1%, 0.05%, 0.03%, and 0.01% of its original density to obtain lower resolution data sets. The software Quick Terrain Modeler (QTM) and its ILAP Bare Earth Extractor Plug-in was used to generate DEMs from the varying point cloud density data sets and the software ENVI was used to perform DEM analysis. It was found that LiDAR point cloud density data set of at least 0.6 points per square meter is necessary to generate an accurate Digital Elevation Model for the test environment.
Book Synopsis Digital Terrain Modeling by : Zhilin Li
Download or read book Digital Terrain Modeling written by Zhilin Li and published by CRC Press. This book was released on 2004-11-29 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by experts, Digital Terrain Modeling: Principles and Methodology provides comprehensive coverage of recent developments in the field. The topics include terrain analysis, sampling strategy, acquisition methodology, surface modeling principles, triangulation algorithms, interpolation techniques, on-line and off-line quality control in data a
Book Synopsis Elevation Data for Floodplain Mapping by : National Research Council
Download or read book Elevation Data for Floodplain Mapping written by National Research Council and published by National Academies Press. This book was released on 2007-08-16 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Floodplain maps serve as the basis for determining whether homes or buildings require flood insurance under the National Flood Insurance Program run by the Federal Emergency Management Agency (FEMA). Approximately $650 billion in insured assets are now covered under the program. FEMA is modernizing floodplain maps to better serve the program. However, concerns have been raised as to the adequacy of the base map information available to support floodplain map modernization. Elevation Data for Floodplain Mapping shows that there is sufficient two-dimensional base map imagery to meet FEMA's flood map modernization goals, but that the three-dimensional base elevation data that are needed to determine whether a building should have flood insurance are not adequate. This book makes recommendations for a new national digital elevation data collection program to redress the inadequacy. Policy makers; property insurance professionals; federal, local, and state governments; and others concerned with natural disaster prevention and preparedness will find this book of interest.
Book Synopsis A Methodology for Processing Raw LIDAR Data to Support Urban Flood Modelling Framework by : Ahmad Fikri Bin Abdullah
Download or read book A Methodology for Processing Raw LIDAR Data to Support Urban Flood Modelling Framework written by Ahmad Fikri Bin Abdullah and published by CRC Press. This book was released on 2020-10-29 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: The consequences of recent floods and flash floods in many parts of the world have been devastating. One way to improving flood management practice is to invest in data collection and modelling activities which enable an understanding of the functioning of a system and the selection of optimal mitigation measures. A Digital Terrain Model (DTM) provides the most essential information for flood managers. Light Detection and Ranging (LiDAR) surveys which enable the capture of spot heights at a spacing of 0.5m to 5m with a horizontal accuracy of 0.3m and a vertical accuracy of 0.15m can be used to develop high accuracy DTM but needs careful processing before using it for any application.This book presents the augmentation of an existing Progressive Morphological filtering algorithm for processing raw LiDAR data to support a 1D/2D urban flood modelling framework. The key characteristics of this improved algorithm are: (1) the ability to deal with different kinds of buildings; (2) the ability to detect elevated road/rail lines and represent them in accordance to the reality; (3) the ability to deal with bridges and riverbanks; and (4) the ability to recover curbs and the use of appropriated roughness coefficient of Manning‘s value to represent close-to-earth vegetation (e.g. grass and small bush).
Book Synopsis Realising the Potential of Airborne LiDAR Data in High Quality DEM Generation by : Xiaoye Liu
Download or read book Realising the Potential of Airborne LiDAR Data in High Quality DEM Generation written by Xiaoye Liu and published by . This book was released on 2009 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: Digital elevation models (DEMs) are becoming increasingly important components in national and regional spatial data infrastructure. High-quality DEMs can now be derived directly from airborne light detection and ranging (LiDAR) point-cloud data of high spatial density if the derivation process can be verified. However, LiDAR is relatively new compared with other technologies for terrain data collection, and, although offering the potential for providing better spatial resolution than those that have been routinely available before, will not diffuse among DEM users until the results of meeting the verification challenge are favourable enough to inspire re-organisation of spatial data in decision support for catchment management and other third-tier-of-government authorities. By way of exemplification, the research presented in this thesis concerned ways of improving the processing of the airborne LiDAR data for high-quality DEM generation in terms of both accuracy and efficiency, and explored the applications of LiDAR-derived DEMs in the region of the Corangamite Catchment Management Authority, Victoria, Australia. This thesis begins with a review of the traditional technologies for terrain data collection and DEM generation and compares them with the LiDAR technology. Accordingly, a review of the recently-reported advances in LiDAR data deployment for DEM generation is followed by reports of experiments designed to improve selection and deployment of LiDAR data filtering, modelling methods and data reduction, and the achievement of vertical accuracy for different land covers. Also reported are results of deployment of LiDAR data for ground truthing, and application of LiDAR data for the extraction of drainage networks on an area of deranged drainage: the Victorian Volcanic Plain. The show that: (a) the issues of filtering, modelling techniques, interpolation methods, DEM resolution, and data reduction are critical and must be considered carefully when using LiDAR data for a high-quality DEM generation; (b) it is efficient to use survey marks for the accuracy assessment of LiDAR data. Normal distribution must be tested in order to select a suitable measure for the accuracy assessment of LiDAR data over different land covers; (c) LiDAR data reduction can improve the terrain production efficiency without compromising the product quality. The deployment of breaklines made a significant contribution to improving the accuracy of terrain models while allowing for data reduction; (d) it demonstrated the practical feasibility of applying ground control points from LiDAR intensity image and LiDAR-derived DEM in image orthorectification. The resultant orthoimage accuracy was shown to be superior to that achieved by using (lower accuracy) data sources such as those from Vicmap data; and (e) the LiDAR-derived DEM offers the capability of extracting and delineating the drainage networks in much more detail in low¬relief terrain, including areas in which drainage is barely coherent; The advantages of using LiDAR-derived DEM over the lower-accuracy DEM emerge in terms of stream order, stream number and stream length.
Book Synopsis Effects of LIDAR Point Density on Bare Earth Extraction and DEM Creation by :
Download or read book Effects of LIDAR Point Density on Bare Earth Extraction and DEM Creation written by and published by . This book was released on 2009 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data density has a crucial impact on the accuracy of Digital Elevation Models (DEMs). In this study, DEMs were created from a high point-density LIDAR dataset using the bare earth extraction module in Quick Terrain Modeler. Lower point-density LIDAR collects were simulated by randomly selecting points from the original dataset at a series of decreasing percentages. The DEMs created from the lower resolution datasets are compared to the original DEM. Results show a decrease in DEM accuracy as the resolution of the LIDAR dataset is reduced. Some analysis is made of the types of errors encountered in the lower resolution DEMs. It is also noted that the percentage of points classified as bare earth decreases as the resolution of the LIDAR dataset is reduced.
Book Synopsis An Assessment of LiDAR-derived DEMs by : Niran M. Pradhan
Download or read book An Assessment of LiDAR-derived DEMs written by Niran M. Pradhan and published by . This book was released on 2008 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uses geographic information systems (GIS) technology to represent the natural terrain of watersheds as digital elevation models (DEMs). Processes light detection and ranging (LiDAR) bare-earth data containing the position (x,y) and the elevation (z) for each point on the surface of the ground to be modeled. Creates different grid size DEMs and compares the associated terrain characteristics.
Book Synopsis The Effects of Data Filtering on Hydraulic Modeling and Floodplain Delineation by : Creighton R. Omer
Download or read book The Effects of Data Filtering on Hydraulic Modeling and Floodplain Delineation written by Creighton R. Omer and published by . This book was released on 2002 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigating Impacts of Natural and Human-induced Environmental Changes on Hydrological Processes and Flood Hazards Using a GIS-based Hydrological/hydraulic Model and Remote Sensing Data by : Lei Wang
Download or read book Investigating Impacts of Natural and Human-induced Environmental Changes on Hydrological Processes and Flood Hazards Using a GIS-based Hydrological/hydraulic Model and Remote Sensing Data written by Lei Wang and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural and human-induced environmental changes have been altering the earth's surface and hydrological processes, and thus directly contribute to the severity of flood hazards. To understand these changes and their impacts, this research developed a GISbased hydrological and hydraulic modeling system, which incorporates state-of-the-art remote sensing data to simulate flood under various scenarios. The conceptual framework and technical issues of incorporating multi-scale remote sensing data have been addressed. This research develops an object-oriented hydrological modeling framework. Compared with traditional lumped or cell-based distributed hydrological modeling frameworks, the object-oriented framework allows basic spatial hydrologic units to have various size and irregular shape. This framework is capable of assimilating various GIS and remotely-sensed data with different spatial resolutions. It ensures the computational efficiency, while preserving sufficient spatial details of input data and model outputs. Sensitivity analysis and comparison of high resolution LIDAR DEM with traditional USGS 30m resolution DEM suggests that the use of LIDAR DEMs can greatly reduce uncertainty in calibration of flow parameters in the hydrologic model and hence increase the reliability of modeling results. In addition, subtle topographic features and hydrologic objects like surface depressions and detention basins can be extracted from the high resolution LiDAR DEMs. An innovative algorithm has been developed to efficiently delineate surface depressions and detention basins from LiDAR DEMs. Using a time series of Landsat images, a retrospective analysis of surface imperviousness has been conducted to assess the hydrologic impact of urbanization. The analysis reveals that with rapid urbanization the impervious surface has been increased from 10.1% to 38.4% for the case study area during 1974 - 2002. As a result, the peak flow for a 100-year flood event has increased by 20% and the floodplain extent has expanded by about 21.6%. The quantitative analysis suggests that the large regional detentions basins have effectively offset the adverse effect of increased impervious surface during the urbanization process. Based on the simulation and scenario analyses of land subsidence and potential climate changes, some planning measures and policy implications have been derived for guiding smart urban growth and sustainable resource development and management to minimize flood hazards.
Book Synopsis GIS-based Analysis of Coastal Lidar Time-Series by : Eric Hardin
Download or read book GIS-based Analysis of Coastal Lidar Time-Series written by Eric Hardin and published by Springer. This book was released on 2014-09-12 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: This SpringerBrief presents the principles, methods, and workflows for processing and analyzing coastal LiDAR data time-series. Robust methods for computing high resolution digital elevation models (DEMs) are introduced as well as raster-based metrics for assessment of topographic change. An innovative approach to feature extraction and measurement of feature migration is followed by methods for estimating volume change and sand redistribution mapping. Simple methods for potential storm impacts and inundation pattern analysis are also covered, along with visualization techniques to support analysis of coastal terrain feature and surface dynamics. Hands-on examples in GRASS GIS and python scripts are provided for each type of analysis and visualization using public LiDAR data time-series. GIS-based Analysis of Coastal Lidar Time-Series is ideal for professors and researchers in GIS and earth sciences. Advanced-level students interested in computer applications and engineering will also find this brief a valuable resource.
Book Synopsis Subdivision Design and Flood Hazard Areas by : James Schwab
Download or read book Subdivision Design and Flood Hazard Areas written by James Schwab and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sustainability, resilience, and climate change are top of mind for planners and floodplain managers. For subdivision design, those ideas haven't hit home. The results? Catastrophic flood damage in communities across the country. This PAS Report is out to end the cycle of build-damage-rebuild and bring subdivision design into line with the best of floodplain planning. Readers will get the tools they need to save lives, protect property, and lay the foundation for a better future.
Book Synopsis Scale Problems in Hydrology by : V.K. Gupta
Download or read book Scale Problems in Hydrology written by V.K. Gupta and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: A special workshop on scale problems in hydrology was held at Princeton University, Princeton, New Jersey, during October 31-November 3, 1984. This workshop was the second in a series on this general topic. The proceedings of the first workshop, held in Caracas, Venezuela, in January 1982, appeared in the Journal of Hydrology (Volume 65:1/3, 1983). This book contains the papers presented at the second workshop. The scale problems in hydrology and other geophysical sciences stem from the recognition that the mathematical relationships describing a physical phenomenon are mostly scale dependent in the sense that different relationships manifest at different space-time scales. The broad scientific problem then is to identify and for mulate suitable relationships at the scales of practical interest, test them experimen tally and seek consistent analytical connections between these relationships and those known at other scales. For example, the current hydrologic theories of evaporation, infiltration, subsurface water transport and water sediment transport overland and in channels etc. derive mostly from laboratory experiments and therefore generally apply at "small" space-time scales. A rigorous extrapolation of these theories to large spatial and temporal basin scales, as mandated by practical considerations, appears very difficult. Consequently, analytical formulations of suitable hydrologic theories at basin wide space-time scales and their experimental verification is currently being perceived to be an exciting and challenging area of scientific research in hydrology. In order to successfully meet these challenges in the future, this series of workshops was initiated.
Book Synopsis Assessment of Vertical Accuracy from UAV-LiDAR and Structure from Motion Point Clouds in Floodplain Terrain Mapping by :
Download or read book Assessment of Vertical Accuracy from UAV-LiDAR and Structure from Motion Point Clouds in Floodplain Terrain Mapping written by and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Remote sensing technologies are being applied to a variety of uses because of the increase in access to various products (digital sensors, UAVs, software) and its ability to model relatively large areas in a short amount of time. While these new technologies are beginning to be adopted, validation of their merit in floodplain terrain mapping is lacking. The main goal of this study is to evaluate the vertical accuracy of digital elevation models (DEMs) generated with UAV-based LiDAR and Structure from Motion (SfM), also known as photographic LiDAR or PhoDAR. Airborne (manned aircraft) LiDAR has been applied to river research in several applications and is common in many fields such as mining, archeology and surveying. SfM has been used to create digital surface models (DSMs) and DEMs of river systems and their associated riparian areas. Given the foundational difference between LiDAR and SfM technologies, the effects of vegetation on the floodplain landscape required a systematic evaluation to determine which techniques are appropriate for floodplain terrain mapping. We collected remotely sensed data from UAV LiDAR and SfM methods at four field sites located within the interior Columbia Basin and analyzed the resulting point clouds and DEMs to determine their vertical accuracy by comparing their elevations with ground surveyed data (checkpoints) throughout the study areas. Both LiDAR and SfM point clouds were filtered and the remaining ground points were compared to surveyed elevations both in their raw form and interpolated DEMs to assess their vertical accuracy. The results show that in vegetated ground cover, LiDAR point clouds were able to produce higher accuracy returns and a resulting higher accuracy DEM than SfM results. In non-vegetated areas, the accuracies between SfM and LiDAR returns are closer but still show higher accuracy from LiDAR point clouds. Ground filtering is shown to be a limitation on DEM vertical accuracy because of the inclusion of non-ground points in the filtering process. This limitation impacts the vertical accuracy of both LiDAR and SfM interpolated DEMs in floodplain habitats.
