This dataset provides an additional "Grazing Potential" land use class to the already-published USGS NAWQA Wall-to-wall Anthropogenic Land-use Trends (NWALT) product (Falcone, 2015, USGS Data Series 948). As with the NWALT, the dataset consists of five national 60-m land use grids, for the years 1974, 1982, 1992, 2002, 2012. The only change to the dataset is, for every year, some pixels which are class 50 "Low-use" in the NWALT, are reclassified to a new class 46 "Grazing Potential Expanded". The purpose of the re-classification is to identify areas which are likely to have had at least some grazing activity based on agreement of historical land cover/use datasets, and not already captured as another land use class by the original NWALT. The re-classification occurred as follows: pixel would otherwise be in class 50 (Low Use), is in an Agriculture or Grazed class in Marschner and Anderson (1967), is in an Agriculture or Rangeland class in 1970s-era GIRAS, and is in a Grassland/Herbaceous class (71) in the NLCD 2011, without restrictions to proximity to water or slope.
Falcone, J.A., 2015, U.S. conterminous wall-to-wall anthropogenic land use trends (NWALT), 19742012: U.S. Geological Survey Data Series 948, 33 p. plus appendixes 36 as separate files, http://dx.doi.org/10.3133/ds948.
Marschner, F.J. and Anderson, J.R., 1967, Major land uses in the United States, U.S. Geological Survey, http://water.usgs.gov/GIS/metadata/usgswrd/XML/na70_landuse.xml