Abstract |
A resource frame is necessary for regional or national scale environmental monitoring so that resources can be selected for sampling with known probability of inclusion. Paper maps have traditionally been used as frames, but they require a significant labor commitment in analog-to-digital conversion. The authors present an automated Geographic Information System (GIS) procedure that creates a lakes frame from the hydrographic layer of the USGS 1:100,000-scale Digital Line Graphs (DLGs). The procedure processes 1:250,000 quad equivalents per run, and is portable to any machine supported by the GIS software. Although developed for the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP), the procedure may be useful to others in environmental management. |