{ "culture": "en-US", "name": "Elevation_2016_DEM_Salcha_Flood_Study", "guid": "", "catalogPath": "", "snippet": "Provide high resolution terrain elevation data from the Tanana River Floodplain Mapping LiDAR dataset.", "description": "

The hydro-flattened and enforced bare earth digital elevation model (DEM) represents the earth's surface with all vegetation and human-made structures removed. It is derived from NIR LiDAR data using TIN processing of the ground point returns. All rivers greater than 30 meters in width and lakes at least 2 acres in size (and smaller as feasible) have been flattened to consistent elevations. Water boundary polygons were developed using an algorithm which weights LiDAR-derived slopes, intensities, and return densities to detect the water's edge. Elevation values were then assigned to the water's edge from the LiDAR data creating 3D breaklines enforced during model creation to flatten water bodies. Additionally, hydro-enforcement breaklines were created at all artificial obstructions to flow found in the ground model (i.e. culverts) to break the obstruction and allow flow to continue. Some elevation values have been interpolated across areas in the ground model where there is no elevation data (e.g. under dense vegetation). The horizontal datum for this dataset is NAD83 (CORS96), the vertical datum is NAVD88, Geoid 06, and the data is projected in Alaska State Plane Coordinate System Zone 3. Units are in U.S. Survey Feet. Quantum Spatial collected the Tanana River Floodplain Mapping LiDAR data for the Fairbanks North Star Borough on 04/30/2016.<\/SPAN><\/P><\/DIV><\/DIV><\/DIV>", "summary": "Provide high resolution terrain elevation data from the Tanana River Floodplain Mapping LiDAR dataset.", "title": "Elevation_2016_DEM_Salcha_Flood_Study", "tags": [ "LiDAR", "Light Detection and Ranging", "elevation data", "topography", "bare earth", "hydro-flattened", "hydro-enforced", "breaklines", "DEM", "digital elevation model", "Fairbanks North Star Borough", "Alaska", "Floodplain", "Mapping", "LiDAR", "DEM" ], "type": "Image Service", "typeKeywords": [ "Data", "Service", "Image Service", "ArcGIS Server" ], "thumbnail": "", "url": "https://gis-pd-img01.local.fnsb.gov:6443/arcgis", "minScale": 288382.88168565964, "maxScale": 4505.982526338432, "spatialReference": "NAD_1983_StatePlane_Alaska_3_FIPS_5003_Feet", "accessInformation": "Fairbanks North Star Borough", "licenseInfo": "

In some areas of heavy vegetation or forest cover, there may be relatively few ground points in the LiDAR data. TINing the points produces large triangles and hence the elevations may be less accurate within such areas. Elevation values for open water surfaces are derived from waters edge breaklines. Triangles were created across water surfaces by interpolating from the nearest breakline elevation points.<\/SPAN><\/P><\/DIV><\/DIV><\/DIV>" }