Elevation - 22 of 42

Elevation FAQs - 42 Found

What are the projection, horizontal and vertical datum, units, and resolution for 3DEP standard DEMs?

All 3DEP seamless DEMs are provided in geographic coordinates (longitude and latitude) in units of decimal degrees, horizontally referenced on the North American Datum of 1983 (NAD83). All elevation values are in units of meters, typically referenced to the North American Vertical Datum of 1988 (NAVD88), although the National Geodetic Vertical Datum of 1929 (NGVD29) and local reference datums are used in some areas outside of the conterminous United States (CONUS). For Hawaii, Puerto Rico, U.S. Virgin Islands, and Pacific Island territories, the vertical datum is typically referenced to local mean sea level. The conterminous U.S. is available at horizontal resolutions of 1 arc-second (approximately 30 meters), and 1/3 arc-second (approximately 10 meters). About 25% of CONUS is available at a resolution of 1/9 arc-second (approximately 3 meters), and a standard 1-meter resolution DEM in UTM coordinates has been produced since January 2015 as new 3DEP lidar is acquired.

Tags: Maps, Topographic, Data Products