For site-specific areas, land cover data has typically been obtained from the interpretation of aerial photography, or digital orthophotography. At the regional level, land cover information is usually produced from the analysis of satellite imagery. The resulting inventory provides accurate information for natural resource applications.
Since July of 1972, the US Landsat satellite system has been providing continuous coverage of multispectral imagery for Illinois. Primary source imagery for the Land Cover of Illinois 1999-2000 initiative has been derived from the Landsat 5 and 7 satellites. Contact the U.S. Geological Surveyfor Landsat program information.
Land is the raw material of Illinois. Current, detailed information about this natural resource is essential for making wise decisions affecting the land and ensuring good stewardship. The terms land use and land cover are commonly used to describe the same type of information. Therefore, some clarification is advisable.
Land use refers to human activities occurring on the land and emphasizes the principal role of land in describing a region's economic activities. Since the concept describes human activity, land use is not directly observable from remote sensing imagery alone. The presence of forested land in an aerial photograph or satellite image does not always convey the possible multiple uses of that land,. These may include recreation, wildlife refuge, timber production, or residential development.
Land cover refers to vegetative and manmade features covering the land surface, all of which can be directly observed using remote sensing imagery. Whereas land use is abstract, land cover is tangible. Land cover information can be determined by direct inspection of the earth surface using remote sensing imagery. Expressed another way, land cover is the visible evidence of land use (Campbell 1987). Furthermore, in areas where natural vegetation predominates, land cover information can be used as a surrogate for ecosystems in natural resource assessments. This is true because vegetation effectively integrates many physical and biological factors within a geographic area (Scott 1993).
Campbell, James B., 1987. Introduction to Remote Sensing, The Guilford Press, 551 p.
Scott, J.M., F. Davis, B. Csuti, R. Noss, B. Butterfield, C. Groves, H. Anderson, S. Caicco, F. D'Erchia, T.C. Edwards, Jr., J. Ulliman, and R.G. Wright, 1993. "Gap Analysis: A Geographic Approach to Protection of Biological Diversity", Wildlife Monograph, No. 123, 41 p.