In 1994, the U.S. Geological Survey (USGS) and National Park Service (NPS) formed a partnership to map U.S. national parks using the National Vegetation Classification (NVC) (TNC and ESRI 1994b). The goals of the USGS-NPS Vegetation Mapping Program (VMP) are to provide baseline ecological data for park resource managers, create data in a regional and national context, and provide opportunities for future inventory, monitoring, and research activities (FGDC 1997, Grossman et al. 1998, http: //biology.usgs.gov/ npsveg/index.html)