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GRASS Help System |
As applications for GRASS have increased, the ability to develop useful, accurate, and up-to-date digital map layers has become very important. Legal boundaries, roads, hydrography, soils, watersheds, and elevation data are among the map layers commonly developed for GRASS databases.
Major sources of national and/or global digital landscape data, and status, coverage and aquisition information about those sources, are identified. This information is extracted from the USACERL Technical Report "Sources of Digital Spatial Data" (Mark Johnson and William Goran, USACERL Technical Report N-88/01/ADA189788). Information is provided on data: format, scale/resolution, coverage, media, costs, and textural descriptions and comments.
This information is needed to assess the cost and time requirements of building a digital database for any specific geographic region. Use of existing digital data sources, rather than construction of new digital data, can result in tremendous savings in both time and money. Also, use of standard sources insures minimum standards for accuracy and quality.
Only national sources are covered. More sources may be available at state agencies such as transportion, environmental, and natural resource management departments. Local planning offices, university geography, urban planning, and civil engineering departments may also provide data.
Further information about specific data sources can be accessed by selecting one of the topic areas listed below: