Irrigated Land - Green River Basin (2001)

This data set is a polygon coverage. It only contains irrigated acreage in the Green River, Little Snake, and Great Divide basin within Wyoming. The initial interpretation of irrigated lands due to the works of man was taken from 1982 and 1983 aerial infra-red photos. The interpretation was then revised with 1999infra-red satellite photography. Upon completion of digitizing these areas, StateEngineer personnel provided comments for proposed alterations to the delineation. The data structure for this data set is based on graph theory, in which a two-dimensional diagram is expressed as a set of spatial objects in a manner that explicitly expresses logical relationships. Applied to a map, this concept is used to encode the spatial relationships between the objects, including such concepts as adjacency and connectivity between objects. A topologically structured data file can support graphic applications,as well as computations and analyses involving the spatial objects and their spatialrelationships. Irrigated lands and sub-irrigated lands are differentiated.