USGS Gap Analysis Project Additional Data: Aspect

Aspect is the compass direction toward which a slope faces, measured in degrees from North in a clockwise direction from 0 to 360. Aspect was generated using ArcGIS Spatial Analyst, with the USGS National Elevation Dataset as input. For quality information regarding the National Elevation Dataset, see http://nationalmap.gov/elevation.html. These data cover the entire continental U.S. and are a continuous data layer. These raster data have a 30 m x 30 m cell resolution. The USGS Gap Analysis Project (GAP) used the best information available to create the aspect data; however GAP seeks to improve and update these data as new information becomes available.