These contour lines provide basic elevation information for earth science studies and mapping applications in the park. The data are utilized by the scientific and resource management communities for change research, hydrologic modeling, resource monitoring, mapping and visualization applications. These contour lines provide the best available public domain vector elevation data of the conterminous USGS topographic quadrangle footprints in a seamless format. These contour lines are derived from diverse source data, processed to a common coordinate system and unit of vertical measure. All contour line data are distributed in Universal Transverse Mercator in units of meters, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are provided in units of feet and are referenced to the North American Vertical Datum of 1988 (NAVD 88) over the conterminous quadrangle boundary footprint.