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To acquire QL2+ lidar detailing surface elevation data, vegetation, and buildings for use to support the 3DEP mission, the Natural Resources Consevation Services (NRCS) Agricultural Drainage Water Management Initiative, National Water Quality Initiative and the Mississippi River Basin Initiative. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 2 US survey feet cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary. |
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To acquire QL2+ lidar detailing surface elevation data, vegetation, and buildings for use to support the 3DEP mission, the Natural Resources Consevation Services (NRCS) Agricultural Drainage Water Management Initiative, National Water Quality Initiative and the Mississippi River Basin Initiative. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 2 US survey feet cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary. |
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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>Product: These lidar data are processed Classified LAS 1.4 files, formatted to 22,208 individual 2000 foot x 2000 foot tiles; used to create intensity images, 3D breaklines and hydro-flattened DEMs as necessary. Geographic Extent: West Central Illinois, covering approximately 3,077 square miles. Counties included are Schuyler, Brown, Menard, Mason, Sangamon, and Morgan. A lidar survey was collected over two (2) areas of interest (AOI) in Illinois identified as the Base AOI and the Option AOI. The Base AOI covers approximately 1,926 square miles in total and the Option AOI covers approximately 1,151 square miles for a total of 3,077 square miles. Dataset Description: West Central Illinois 2017 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.5 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2; Quality Level 2+. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane Coordinate System Illinois West (FIPS 1202), US Survey Feet and vertical datum of NAVD88 (GEOID12B), US Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 22,208 individual 2000 foot x 2000 US survey feet tiles, as 22,208 tiled Intensity Imagery, and as 22,209 tiled bare earth DEMs; all tiled to the same 2000 foot x 2000 foot schema. In an effort to preserve smooth continuity of the surface in which there are multiple overlapping swaths, an isolated area of cross flight line 229 was bit set at withheld in the following nine tiles: 2207_1295, 2207_1293, 2209_1297, 2209_1295, 2209_1293, 2311_1297, 2311_1295, 2311_1293, and 2313_1297. One tile located in Mason County, titled 2353_1367, did not contain LAS points as it consisted strictly of water with no ground points present. Therefore, no intensity image TIF could be produced for this tile, only a hydro-flattened DEM image is available. This tile is included in the tile index consisting of 22,209 tiles. Ground Conditions: Lidar was collected in December 2017, while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Surveying and Mapping, LLC (SAM) established a total of 63 ground control points that were used to calibrate the lidar to known ground locations established throughout the Base AOI and Option AOI project areas. An additional 162 independent accuracy checkpoints, 91 in Bare Earth and Urban landcovers (91 NVA points), 71 in tall Grass/tall weeds/crops, Brush lands/short trees, Forested categories (71 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.</SPAN></P></DIV></DIV></DIV> |
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["Model","LAS Point Cloud","Classified LAS","Swath LAS","Remote Sensing","Elevation Data","Lidar","Digital Elevation Model","Breaklines"] |