New Land Cover Maps Capture Nearly Two Decades of Change Across the U.S.

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The U.S. Geological Survey recently released updated land cover maps for the conterminous United States that depict 18 years of change to the Nation’s landscapes. New maps comparing the 2001 to 2019 National Land Cover Databases show that more than 10 percent of land cover in the Lower 48 states changed during that time, largely in forested areas.

The U.S. Geological Survey recently released updated land cover maps for the conterminous United States that depict 18 years of change to the Nation’s landscapes.

 New maps comparing the 2001 to 2019 National Land Cover Databases show that more than 10 percent of land cover in the Lower 48 states changed during that time, largely in forested areas.

The latest database, NLCD 2019, also offers the following upgrades for understanding landscape change:

  • A new data layer maps wind energy development.
  • By filling in historical impervious surface data back to 2001, the new data enables robust comparisons of urban development and intensity across the eight epochs (calendar years) represented by NLCD—2001, 2004, 2006, 2008, 2011, 2013, 2016, and 2019.

The database builds on the 2016 accuracy, which was the highest ever for NLCD of 91%, by correcting previous errors across all land cover classes. The USGS and its partners at the interagency Multi-Resolution Land Characteristics (MRLC) consortium created the NLCD 2019 database from Landsat satellite data faster than any other database in the project’s two-decade history. Production teams replaced the Landsat scene-based approach to one based on Landsat composites, allowing them to automate some of the production steps, according to EROS Geographer and NLCD Manager Jon Dewitz. This freed up more time to characterize the difficult-to-classify pixels that require human interpretation.

Each of the map’s nine billion pixels is based on Landsat’s 30-meter resolution, which represents an area around the size of a baseball infield. Each of these “infields” are sorted into 16 land cover classes such as deciduous forest, high-intensity developed, hay/pasture and related groupings.

NLCD also works with partners like LANDFIRE and the National Agriculture Statistics Service (NASS) to refine and improve its land cover classifications. Such collaboration benefits users of NLCD products, which are among the most widely used Landsat-derived datasets produced by the USGS. The core publications related to NLCD have been cited nearly 7,700 times across hundreds of different subject areas, according to Elsevier’s Scopus database. 

NLCD also recently collaborated with MRLC partner National Oceanic and Atmospheric Administration (NOAA) to create another online portal to aid in the understanding land cover and change in the U.S.: the Enhanced Visualization and Analysis (EVA) tool. The tool lets users pick any county in the U.S. and create a custom report on change to land cover, developed areas, cropland change, and more. The change estimates act as a snapshot, breaking down land cover in charts and change percentages, as opposed to presenting the information in a GIS mapping format.

The NLCD Viewer tool allows users to zoom in to their area of interest, scan for change, download data year by year, or download animations of change over time at no cost. To learn more and access the new datasets, visit mrlc.gov.

The suite of GIS mapping products from the USGS National Land Cover Database

The suite of GIS mapping products from the USGS National Land Cover Database includes a layer that defines the intensity of impervious surfaces across the U.S. This data factors into runoff modeling, urban heat, and much more. NLCD 2019 includes impervious surface layers for eight separate calendar years, allowing users to compare changes to urban areas. This image compares the impervious surfaces of Boise, ID from 2001, 2008, and 2019.

(Public domain.)