NED data for the conterminous United States, Hawaii, Puerto Rico, the Pacific Islands, and the Samoan Islands is expressed in geographic coordinates (latitude/longitude). It is horizontally referenced to the North American Datum of 1983 (NAD83) and vertically referenced to the North American Vertical Datum of 1988 (NAVD88). The resolution is one arc-second (approximately 30 meters). NED data is also available at 1/3 arc-second resolution (approximately 10 meters) for some areas of the conterminous United States.
Data processed by Connie Hoong choong@usgs.gov, 808-587-2427 USGS, 677 Ala Moana Blvd., Suite 415, Honolulu, HI, 96816