We give credit to Francis J. Marschner and James R. Anderson. The USGS National Water Summary program supported the effort to digitize the hard copy of the map. Dick Paulson checked color plots of all states except Alaska and Hawaii. The data is complete for the coterminous United States. Current as of publication date.
Land use spatial delineations and codes.
The following is an overall description of the procedures used to prepare the data set. The detailed processing steps are listed afterwards. Jack Wittmann from USGS-NMD supplied a clear plastic overlay of the linework for the National Atlas plate. The plastic overlay was scanned on the TEK 4991 drum scanner in the Reston GIS lab. After polygon topology was built, interior polygons having small areas were checked and the ones that were not part of the land use categories were removed.