Data - Removing roads from the National Land Cover Database to create improved urban maps for the United States, 1992-2011

To better map the urban class and understand how urban lands change over time, we removed rural roads and small patches of rural development from the NLCD developed class and created four wall-to-wall maps (1992, 2001, 2006, and 2011) of urban land. Removing rural roads from the NLCD developed class involved a multi-step filtering process, data fusion using geospatial road and developed land data, and manual editing. Reference data classified as urban or not urban from a stratified random sample was used to assess the accuracy of the 2001 and 2006 urban and NLCD maps. The newly created urban maps had higher overall accuracy (98.7%) than the NLCD maps (96.2%). More importantly, the urban maps resulted in lower commission error of the urban class (23% versus 57% for the NLCD in 2006) with the trade-off of slightly inflated omission error (20% for the urban map, 16% for NLCD in 2006). The removal of approximately 230,000 km2 of rural roads from the NLCD developed class resulted in maps that better characterize the urban footprint. These urban maps are more suited to modeling applications and policy decisions that rely on quantitative and spatially explicit information regarding urban lands. Digital maps of urban land in the United States for 1992, 2001, 2006, and 2011 are available (at a 30-m pixel resolution) as four compressed 2-bit IMG files. The map year is reflected in the file name.

                                            [
  "010:12"
]
                                        

                                            {
  "fn": "Christopher E Soulard",
  "@type": "vcard:Contact",
  "hasEmail": "mailto:csoulard@usgs.gov"
}
                                        

                                            [
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                                            [
  "USA",
  "USGS:59ee2ea2e4b0220bbd975a5e",
  "United States",
  "cities",
  "imageryBaseMapsEarthCover",
  "land use change",
  "populated places",
  "structure",
  "transportation",
  "urban"
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                                            {
  "name": "U.S. Geological Survey",
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                                            [
  "Geospatial"
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