Summary

Description

This dataset provides a U.S. national 60-m, 19-class mapping of anthropogenic land uses for five time periods: 1974-1982-1992-2002-2012. The 2012 dataset is based on a slightly modified version of the National Land Cover Database 2011 (NLCD 2011) that was recoded to a schema of land uses, and mapped back in time to develop datasets for the four earlier eras. The time periods coincide with years in which U.S. Department of Agriculture (USDA) Census of Agriculture data were collected. Changes are derived from (a) known changes in water bodies from reservoir construction or removal, (b) housing unit density changes, (c) regional mining/extraction trends, (d) for 1999-2012, timber and forestry activity based on US Geological Survey (USGS) Landfire data, (e) county-level USDA Census of Agriculture change in cultivated land, and (f) establishment dates of major conservation areas. The data are compared to several other published studies and datasets as validation. Caveats are provided about limitations of the data for some classes. The work was completed as part of the USGS National Water-Quality Assessment (NAWQA) Program and termed the NAWQA Wall-to-Wall Anthropogenic Land Use Trends (NWALT) dataset, with anticipation of five year updates for future versions. The associated datasets include five 60-m geospatial rasters showing anthropogenic land use from 1974-2012 and 14 rasters showing the extent of timber clear-cutting and harvest for 1999-2012. The full report for the product is provided as USGS Data Series 2015-948, at http://dx.doi.org/10.3133/ds948.