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GRASS Help System |
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Major Category - Subdivision | References
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Elevation |
- terrestrial | DMA USGS NGDC
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- marine (bathymetry) | NGDC
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Imagery |
- satellite |
> multispectral | SPOT EOSAT NGDC
> weather | NCDC NGDC
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- airborne |
> multispectral | EPA
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Geomorphic |
- seismic | NGDC
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- soils | SCS
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- geology | NGDC
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Topological |
- landuse/landcover | USGS
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- political/census boundaries | USGS USBC
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- hydrologic units | USGS
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- transportation | USGS
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