ADCi Digital Elevation Models (DEM)
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Data Source
1:24,000 scale United States Geological Survey (USGS); 30 meter grid. Map features larger than 90 meters will generally be represented.
Contents
The contour lines are created from points arranged in columns aligned with the UTM grid.
A contour interval is specified when the map is ordered. The recommended interval for 1:24,000 scale data should be 40 feet for best accuracy and not less than 20 feet.
ADCi will edge-match a limited number of contours across quadrangle boundaries. Upon special request we can provide index contours and contour labels.
Coverage
Available for 100% of the 7.5' quads in the United States.
Suggested Uses
- Line of Sight (LOS) analysis
- Terrain analysis for radio and TV signal propagation
- Civil and environmental presentations
- Airport design and mining
- Flood Plain Analysis
Formats
ESRI - shape (.shp) and File GeoDatabase format - (1 TB limit per dataset) Must have version 9.2
MapInfo - .TAB and mid/mif
AutoCAD - .dwg
MicroStation - .dgn
Coordinate Systems
Geographic Decimal Degrees (Lat/Long) - WGS84, NAD83, NAD27
State Plane Coordinates (SPC) - NAD83 feet or meters, NAD27 feet or meters
Universal Transverse Mercator (UTM) - NAD83 feet or meters, NAD27 feet or meters.
