{ "culture": "en-US", "name": "IL_St_Clair_DTM_2012", "guid": "", "catalogPath": "", "snippet": "These acquisitions of the LiDAR data and its derivatives were made possible by a grant from the National Geodetic Survey for the National Height Modernization Program. The program is in place to enable states access to accurate, reliable heights using global positioning satellite (GPS) technology in conjunction with traditional leveling, gravity, and modern remote sensing technologies. LiDAR data and its derivatives assist in real-world uses around the state of Illinois such as; highway engineering, flood prediction, agricultural land management, mining subsidence, monitoring archaeological features, locating sinkholes and applied geologic science.\n\nThe data do not replace the need for detailed site-specific studies. The information is not appropriate for, and is not to be used as, a geodetic, legal, or engineering base. The information has no legal basis in the definition of boundaries or property lines and is not intended as a substitute for surveyed locations such as can be determined by a registered Public Land Surveyor.", "description": "

This Digital Terrain Model (DTM) data was produced all or in part from LiDAR information as of 2012. The LiDAR derived DTM covers St. Clair County, Illinois and include inland streams, rivers, lakes ponds and tidal features. These data are appropriate for use in local and regional analysis. This data set has a vertical accuracy of 6.09 centimeters RMSEz, and point spacing of 1.0 meters. Digital Elevation Models (including terrain and surface models) are raster data sets created from whole LiDAR point cloud data sets (LAS files). The LAS files are the standard LiDAR file format which contains the raw point cloud data, these data are normally classified and distinguished between points on the ground, water or elevated features such as buildings, trees, towers, bridges, etc.. These LAS files are processed into elevation models to create gridded rasters. The first returns can be used to map the top reflective surface (Digital Surface Models - DSM), these normally include open terrain areas, as well as the tops of buildings, trees, towers, and other features elevated above the bare earth. The last returns are used to map the bare-earth terrain (Digital Terrain Models - DTM), these are normally produced with irregularly-spaced points rather than the uniform grid structure of a Digital Elevation Model (DEM), Digital Terrain Models will often include breaklines to help define edges of water bodies.<\/SPAN><\/P><\/DIV><\/DIV>", "summary": "These acquisitions of the LiDAR data and its derivatives were made possible by a grant from the National Geodetic Survey for the National Height Modernization Program. The program is in place to enable states access to accurate, reliable heights using global positioning satellite (GPS) technology in conjunction with traditional leveling, gravity, and modern remote sensing technologies. LiDAR data and its derivatives assist in real-world uses around the state of Illinois such as; highway engineering, flood prediction, agricultural land management, mining subsidence, monitoring archaeological features, locating sinkholes and applied geologic science.\n\nThe data do not replace the need for detailed site-specific studies. The information is not appropriate for, and is not to be used as, a geodetic, legal, or engineering base. The information has no legal basis in the definition of boundaries or property lines and is not intended as a substitute for surveyed locations such as can be determined by a registered Public Land Surveyor.", "title": "IL_St_Clair_DTM_2012", "tags": [ "Light Detection and Ranging", "LiDAR", "Bare Earth", "Point Cloud", "Digital Elevation Model", "DEM", "Elevation", "Surface Model", "Digital Surface Model", "DSM", "Hillshade" ], "type": "Image Service", "typeKeywords": [ "Data", "Service", "Image Service", "ArcGIS Server" ], "thumbnail": "", "url": "https://isgs-datagis1:6443/arcgis", "spatialReference": "NAD_1983_NSRS2007_Transverse_Mercator", "accessInformation": "Merrick & Co. Illinois State Geological Survey, Illinois Department of Transportation", "licenseInfo": "

ISGS information is the property of and copyrighted by the Board of Trustees of the University of Illinois with all rights reserved. University copyright policy is stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4. A link is provided in the Cross References section. Individuals or entities may make fair use of copyrighted ISGS material, such as reproducing a single figure or table, or using a brief text quotation, without obtaining formal permission, but in all cases the Illinois State Geological Survey must be credited as the source of the material. To reproduce ISGS information beyond the fair use standard, permission must be obtained from the ISGS Information Office, 615 East Peabody Drive, Champaign, Illinois 61820, 217-333-4747, isgs@isgs.illinois.edu. License fees and a license agreement may be required, depending on the proposed usage. Any use of these data is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice. Links to these are provided in the Cross References section. Map information is to be used at a scientifically and cartographically appropriate scale, that is, at a scale no greater than indicated on the map or as described in the documentation of the map or map data. Map information is not appropriate for, and is not to be used as, a geodetic, legal, or engineering base. Map information has no legal basis in the definition of boundaries or property lines and is not intended as a substitute for surveyed locations such as can be determined by a registered Public Land Surveyor. The data do not replace the need for detailed site-specific studies.<\/SPAN><\/P><\/DIV><\/DIV>" }