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


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Soulard, C.E., and Acevedo, William, 2017, Data - Removing roads from the National Land Cover Database to create improved urban maps for the United States, 1992-2011: U.S. Geological Survey data release,


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 [...]


Point of Contact :
Christopher E Soulard
Originator :
Christopher E Soulard, William Acevedo
Metadata Contact :
Christopher E Soulard
Publisher :
U.S. Geological Survey
Distributor :
U.S. Geological Survey - ScienceBase
USGS Mission Area :
Land Resources
SDC Data Owner :
Western Geographic Science Center

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Urban Areas - Project Level Metadata.xml
Original FGDC Metadata

29.06 KB
Urban Areas 254.48 MB


Quantifying change in urban land provides important information to create empirical models examining the effects of human land use. Maps of developed land from the National Land Cover Database (NLCD) of the conterminous United States include rural roads in the developed land class and therefore overestimate the amount of urban land. Additionally, commission errors of the NLCD developed class occur because the road network includes primary and secondary roads that are delineated three or more 30-meter pixels wide, and tertiary roads including gravel tracks and logging routes. Most roads are not wider than 90 meters, which means that NLCD often over-represents actual road area. Road density is inconsistent, with large differences between the western and eastern United States stemming from the use of automated processes in the west to reduce the mapping of dirt tracks through rural areas. Finally, NLCD treats the road network as a static input across the 2001, 2006, and 2011 map dates, unlike the rest of the developed footprint that changes dynamically over time. To more accurately represent this urban component of developed lands and better understand how urban land changes over time, errors attributable to including rural roads in the NLCD developed class were resolved. We developed a benchmark method to modify NLCD and create a consistent product representative of urban land cover in the conterminous United States, with corresponding accuracy estimates.


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DOI doi:10.5066/F79G5K05

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