Current and historical land use (how land is used) and land cover (the type of vegetation in an area) can be identified using many different types of map products. Before settlement, early surveyors were sent out to map the land. In the process, they noted resources and vegetation. Since the 1930s, aerial photography has been used to learn about land use and cover. The following sites can be used to find information about land use and cover in Illinois, McDonough County, and other areas of the United States.
Orthophotos are photographs that have been corrected for camera tilt, relief and perspective. Orthophoto quadrangles cover the same area as a standard 1:24,000 topographic map.