Irrigated Land - Bear River Basin (2001)

This data set is a polygon coverage. It only contains irrigated acreage in the Bear River Basin within or near Wyoming. The interpretation of irrigated lands due to the works of man was taken from 1982 and 1983 aerial infra-red photos. Upon completion of digitizing these areas, Wyoming State Engineer's Office field personnel updated the lands and checked the accuracy of the delineation. Their check was completed in the fall of 1998. The data structure for thi 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 spatial relationships.