The USGS National Elevation Dataset (NED) has been developed by merging the highest-resolution, best-quality elevation data available across the United States into a seamless raster format

This file is in Global Mapper Package (GMP) format.

FILENAME=man_topprints.shp
DESCRIPTION=man_topprints.shp
AREA COUNT=2414
AREA VERTEX COUNT=15917
LINE COUNT=0
POINT COUNT=0
UPPER LEFT X=-74.0190113097
UPPER LEFT Y=40.7275820810
LOWER RIGHT X=-73.9938899469
LOWER RIGHT Y=40.7004250182
WEST LONGITUDE=74° 01' 8.4407" W
NORTH LATITUDE=40° 43' 39.2955" N
EAST LONGITUDE=73° 59' 38.0038" W
SOUTH LATITUDE=40° 42' 1.5301" N
PROJ_DESC=Geographic (Latitude/Longitude) / WGS84 / arc degrees
PROJ_DATUM=WGS84
PROJ_UNITS=arc degrees
EPSG_CODE=4326
COVERED AREA=2.47 sq mi

Sample of DEM which is elevations in a regular grid, derived from USGS topographic map contours or directly from aerial photography.