Upper Gunnison Basin Land Cover
The Upper Gunnison Basin is a high-elevation ecosystem in Colorado ranging in elevations from 2200 to 4300 m above sea level.
Mapping of the Upper Gunnison Basin's land cover has been limited by the diverse and often incompatible needs of the federal agencies managing resources in the Basin and the lack of digital technology. Numerous large-scale maps, typically of 1:24,000 scale, have documented the spatial distribution of potential vegetation in selected areas. The only Basin-wide coverage of land cover and vegetation is a series of 1:126,720 scale maps produced by the Soil Conservation Service (USDA 1976a, 1976b, 1976c). While these maps delineate broad forest types, they combine all non-forested areas of the Basin as range. While most of the existing maps were derived through color aerial photo interpretation, considerable information is lost in the production of analog maps, and the possibility of subsequent data analysis is limited. Much more desirable are digital land cover maps developed and analyzed with geographic information systems (Coulson et al. 1991, Sample 1994, USDA 1995). Such maps layers can be compared to other spatial layers such as soil types, geologic substrates, landforms, and elevation. Development of multiple map layers, including a vegetation layer, will provide a valuable GIS database for use in ecological and geological research, land management decisions, and GIS coursework at Western.
This mapping project includes all portions of the Upper Gunnison Basin that drain into the Gunnison River above the Black Canyon of the Gunnison River (Blue Mesa Dam). This basin is delineated by the continental divide to the east and south, the Elk Mountains to the north, and the West Elk Mountains, Soap Mesa, Alpine Plateau, and the San Juan Mountains to the west.North American Landscape Characterization project. Two MSS images ( path 034, row 033; and path 034, row 034; 07/05/92) were concatenated. The outline of the Upper Gunnison Basin was then digitized and georeferenced. The resulting vector layer was converted to a polygon raster layer, which was then applied to the satellite image to eliminate areas outside the boundaries of the basin. Cloud cover and shadows were removed through filtering and the overlaying of 1983 MSS data where needed. These corrections modified less than 5 % of the map area.
The MSS data has been insufficient in spatial detail and discrete reflectances to provide land cover maps of higher discrimination. Use of Landsat thematic mapper (TM) data is expected to provide the resolution and spectral bands necessary to further refine our land cover map(USGS 1996b).
Coulson, R.N., C.N. Lovelady, R.O. Flamm, S.L. Spradling, and M.C. Saunders. 1991. Intelligent geographic information systems for natural resource management. pp 153-172. In: Quantitative methods in landscape ecology. Turner, M.G. and R.H. Gardner, eds. Springer-Verlag, New York.
North American Landscape Characterization (NALC) Http://edcww.cr.usgs.gov/glis/hyper/guide/nalc
Sample, V.A. 1994. Realizing the potential of remote sensing and GIS in ecosystem management planning, analysis, and policymaking. pp 346-352. In: Remote sensing and GIS in ecosystem management. Sample, V.A., ed. Island Press, Washington, D.C..
USDA 1976a. Land use and natural communities: Gunnison County, Colorado. United States Department of Agriculture, Soil Conservation Service, Portland, Oregon.
USDA 1976b. Land use and natural communities: Hinsdale County, Colorado. United States Department of Agriculture, Soil Conservation Service, Portland, Oregon.
USDA 1976c. Land use and natural communities: Saguache County, Colorado. United States Department of Agriculture, Soil Conservation Service, Portland, Oregon.
USDA 1995. Guidelines for the Use of Digital Imagery for Vegetation Mapping. United States Department of Agriculture, Forest Service Engineering Staff. Washington D.C..
USGS 1996a. 1-Degree USGS Digital Elevation Models. United States Geological Survey..
USGS 1996b. Thematic Mapper Landsat Data. United States Geological Survey.