Summary

Description

The Grayscale Shaded Relief of the Conterminous United States map layer is a 100-meter resolution grayscale shaded relief image of the United States, in an Albers Equal-Area Conic projection. Shaded relief was created with the ArcGIS Hillshade command, with 45-degree sun elevation, 315-degree azimuth, and a z-factor of 1.0. Very dark and very light shades both represent steeper terrain. Mid-range grays represent flatter terrain. The grayscale shaded relief data were derived from the National Atlas 100-meter resolution elevation data. The elevation data were derived from 2012 National Elevation Dataset (NED) data and show the terrain of the conterminous United States at a resolution of 100 meters. The NED is a raster product assembled by the U.S. Geological Survey, designed to provide national elevation data in a seamless form with a consistent datum, elevation unit, and projection. Data corrections made in the NED assembly process minimize artifacts, permit edge matching, and fill sliver areas of missing data. More information on NED can be found at http://ned.usgs.gov.