NLCD 2021: USGS National Land Cover Database, 2021 release

USGS/NLCD_RELEASES/2021_REL/NLCD
Dataset Availability
2021-01-01T00:00:00Z–2022-01-01T00:00:00Z
Dataset Provider
Earth Engine Snippet
ee.ImageCollection("USGS/NLCD_RELEASES/2021_REL/NLCD")
Tags
blm landcover landuse-landcover mrlc nlcd usgs

Description

The U.S. Geological Survey (USGS), in partnership with several federal agencies, has now developed and released seven National Land Cover Database (NLCD) products: NLCD 1992, 2001, 2006, 2011, 2016, 2019, and 2021. Beginning with the 2016 release, land cover products were created for two-to-three-year intervals between 2001 and the most recent year. These products provide spatially explicit and reliable information on the Nation’s land cover and land cover change. NLCD continues to provide innovative, consistent, and robust methodologies for production of a multi-temporal land cover and land cover change database.

The NLCD 2021 release is update based, so the Land Cover and Impervious Surface products released in 2019 are unchanged and used directly with NLCD 2021 for change analysis though the NLCD timespan. Science products and the change index are updated and will need to be reacquired to contain the additional 2021 change. These new products use a streamlined compositing process for assembling and preprocessing Landsat imagery and geospatial ancillary datasets; a temporally, spectrally, and spatially integrated land cover change analysis strategy; a theme-based post-classification protocol for generating land cover and change products; a continuous fields biophysical parameters modeling method; and a scripted operational system. The overall accuracy of the 2019 Level I land cover was 91%. Results from this study confirm the robustness of this comprehensive and highly automated procedure for NLCD 2021 operational mapping (see doi:10.1080/15481603 for the latest accuracy assessment publication). Questions about the NLCD 2021 land cover product can be directed to the NLCD 2021 land cover mapping team at USGS EROS, Sioux Falls, SD (605) 594-6151 or mrlc@usgs.gov. See included spatial metadata for more details.

Please see National Land Cover Database (NLCD) 2019 NLCD release for the 2019 release of NLCD which is used with the 2021 release for comparisons through the years. Also refer to the larger NLCD Community page for all things NLCD related National Land Cover Database (NLCD) NLCD Community Page.

Bands

Pixel Size
30 meters

Bands

Name Units Min Max Pixel Size Description
landcover 11 95 meters

All images include the landcover classification scheme described in the Product Legend. The legends are also available as metadata on each image. The classes in the product legend are given below.

impervious % 0 100 meters

Percent of the pixel covered by developed impervious surface.

impervious_descriptor 20 29 meters

Defines which impervious layer pixels are roads and provides the best fit description for impervious pixels that are not roads.

science_products_land_cover_change_count 1 8 meters

These products were developed as both intermediate steps to generate the base NLCD products, and as value added products that standalone to provide additional insights. This product was derived using the 9-epoch NLCD land cover (2001, 2003, 2006, 2008, 2011, 2013, 2016, 2019, and 2021) from the released NLCD 2021 product suite. Any change between two consecutive epochs is calculated and the total change frequency/time for each pixel is recorded. This product shows an integer count total of any recorded change for the time period 2001-2021. This product is meant to be used with the change index and individual dates of Land Cover to provide users with a more in depth look at where multiple change events in the same location are occurring on the landscape. All images include the Science Products classification scheme follow the Land Cover system and are described in the Product Legend. The legends are also available as metadata on each image. The classes in the product legend are given below.

science_products_land_cover_change_first_disturbance_date 1 9 meters

These products were developed as both intermediate steps to generate the base NLCD products, and as value added products that standalone to provide additional insights. This product was derived using the nine release dates of NLCD land cover (2001, 2003, 2006, 2008, 2011, 2013, 2016, 2019, 2021). This product shows the date of the first land cover change event from these 9 dates of landcover. All images include the Science Products classification scheme follow the Land Cover system and are described in the Product Legend. The legends are also available as metadata on each image. The classes in the product legend are given below.

science_products_land_cover_change_index 1 13 meters

These products were developed as both intermediate steps to generate the base NLCD products, and as value added products that standalone to provide additional insights. The NLCD Land Cover change index combines information from all years of land cover change and provides a simple and comprehensive way to visualize change from all 9 dates of land cover in a single layer. The change index was designed to assist NLCD users to understand complex land cover change with a single product. NLCD 2021 does not yet contain updated products for Alaska, Hawaii and Puerto Rico. All images include the Science Products classification scheme follow the Land Cover system and are described in the Product Legend. The legends are also available as metadata on each image. The classes in the product legend are given below.

science_products_land_cover_science_product 11 95 meters

These products were developed as both intermediate steps to generate the base NLCD products, and as value added products that standalone to provide additional insights. To better develop NLCD 2021 landcover, spectrally stable grass and shrub areas were separated from the spectrally changing areas of shrub and grass represented by forest harvest, burns, regrowth, and other disturbances. Essentially, this separation usually identifies shrub and grass climax areas from shrub and grass areas in transition back to a forest. This difference is expressed with two extra classes of land cover, called Shrub-Forest and Herbaceous-Forest which are representing areas of current shrub and grass expected to transition back to a forest. Alternatively, the shrub and grass classes of Shrub/Scrub and Grassland/Herbaceous will likely not transition to a forest. However, be cautioned that no extensive ecological analysis went into these class delineations, they are primarily spectral based separations used to delineate broad classes of grass and shrub. All images include the Science Products classification scheme follow the Land Cover system and are described in the Product Legend. The legends are also available as metadata on each image. The classes in the product legend are given below.

science_products_forest_disturbance_date 83 200 meters

These products were developed as both intermediate steps to generate the base NLCD products, and as value added products that standalone to provide additional insights. This product shows the most recent forest disturbance date between the years 1986-2021 for every year. This product combines information from the NLCD 2021 change detection, land cover classification, and the LANDFIRE Vegetation Change Tracker (VCT) disturbance product from 1984-2010. For NLCD 2021, this product was used to assess where disturbance occurred for forest areas. This product was originally intended only for forest areas, but it also can be useful for other landcover classes. For example, agricultural areas, which are typically disturbed yearly by tillage, are represented as being disturbed prior to 1986. This "prior to 86" disturbance call was used in some instances as a delineation between forested and non-forest areas. Other classes that are not forest may also be represented with a disturbance indication if the area was forest at some time point during 1986-2021. All images include the Science Products classification scheme follow the Land Cover system and are described in the Product Legend. The legends are also available as metadata on each image. The classes in the product legend are given below.

landcover Class Table

Value Color Description
11 #466b9f

Open water: areas of open water, generally with less than 25% cover of vegetation or soil.

12 #d1def8

Perennial ice/snow: areas characterized by a perennial cover of ice and/or snow, generally greater than 25% of total cover.

21 #dec5c5

Developed, open space: areas with a mixture of some constructed materials, but mostly vegetation in the form of lawn grasses. Impervious surfaces account for less than 20% of total cover. These areas most commonly include large-lot single-family housing units, parks, golf courses, and vegetation planted in developed settings for recreation, erosion control, or aesthetic purposes.

22 #d99282

Developed, low intensity: areas with a mixture of constructed materials and vegetation. Impervious surfaces account for 20% to 49% percent of total cover. These areas most commonly include single-family housing units.

23 #eb0000

Developed, medium intensity: areas with a mixture of constructed materials and vegetation. Impervious surfaces account for 50% to 79% of the total cover. These areas most commonly include single-family housing units.

24 #ab0000

Developed high intensity: highly developed areas where people reside or work in high numbers. Examples include apartment complexes, row houses, and commercial/industrial. Impervious surfaces account for 80% to 100% of the total cover.

31 #b3ac9f

Barren land (rock/sand/clay): areas of bedrock, desert pavement, scarps, talus, slides, volcanic material, glacial debris, sand dunes, strip mines, gravel pits, and other accumulations of earthen material. Generally, vegetation accounts for less than 15% of total cover.

41 #68ab5f

Deciduous forest: areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total vegetation cover. More than 75% of the tree species shed foliage simultaneously in response to seasonal change.

42 #1c5f2c

Evergreen forest: areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total vegetation cover. More than 75% of the tree species maintain their leaves all year. Canopy is never without green foliage.

43 #b5c58f

Mixed forest: areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total vegetation cover. Neither deciduous nor evergreen species are greater than 75% of total tree cover.

52 #ccb879
71 #dfdfc2
81 #dcd939
82 #ab6c28

Cultivated crops: areas used for the production of annual crops, such as corn, soybeans, vegetables, tobacco, and cotton, and also perennial woody crops such as orchards and vineyards. Crop vegetation accounts for greater than 20% of total vegetation. This class also includes all land being actively tilled.

90 #b8d9eb

Woody wetlands: areas where forest or shrubland vegetation accounts for greater than 20% of vegetative cover and the soil or substrate is periodically saturated with or covered with water.

95 #6c9fb8

Emergent herbaceous wetlands: areas where perennial herbaceous vegetation accounts for greater than 80% of vegetative cover and the soil or substrate is periodically saturated with or covered with water.

impervious_descriptor Class Table

Value Color Description
0 #000000

Unclassified.

20 #ff0000

Primary road. Interstates and other major roads. Pixels were derived from the 2018 NavStreets Street Data.

21 #ffff00

Secondary road. Non-interstate highways. Pixels were derived from the 2018 NavStreets Street Data.

22 #0000ff

Tertiary road. Any two-lane road. Pixels were derived from the 2018 NavStreets Street Data.

23 #ffffff

Thinned road. Small tertiary roads that generally are not paved and have been removed from the landcover but remain as part of the impervious surface product. Pixels were derived from the 2018 NavStreets Street Data.

24 #ffc0c5

Non-road non-energy impervious. Developed areas that are generally not roads or energy production; includes residential/commercial/industrial areas, parks, and golf courses.

25 #eb82eb

Microsoft buildings. Buildings not captured in the NLCD impervious process, and not included in the nonroad impervious surface class. Pixels derived from the Microsoft US Building Footprints dataset.

26 #9f1feb

LCMAP impervious. Impervious pixels from LCMAP that were used to fill in gaps left when roads were updated from previous versions of NLCD.

27 #40dfd0

Wind turbines. Pixels derived from the US Wind Turbine Dataset, accessed on 1/9/2020.

28 #79ff00

Well pads. Pixels derived from the 2019 Oil and Natural Gas Wells dataset from the Oak Ridge National Laboratory.

29 #005f00

Other energy production. Areas previously identified as well pads and wind turbines and classified in coordination with the Landfire project.

science_products_land_cover_change_count Class Table

Value Color Description
1 #0000ff

change once 2001-2019

2 #00d0ff

change twice 2001-2019

3 #00fffa

change three times 2001-2019

4 #00ff7d

change four times 2001-2019

5 #79ff00

change five times 2001-2019

6 #ffff00

change six times 2001-2019

7 #ffd000

change seven times 2001-2019

8 #ff0000

change eight times 2001-2021

science_products_land_cover_change_first_disturbance_date Class Table

Value Color Description
1 #005f00

land cover no change

2 #0000ff

land cover change 2001-2004

3 #00d0ff

land cover change 2004-2006

4 #00fffa

land cover change 2006-2008

5 #00ff7d

land cover change 2008-2011

6 #79ff00

land cover change 2011-2013

7 #ffff00

land cover change 2013-2016

8 #ffd000

land cover change 2016-2019

9 #ff0000

land cover change 2019-2021

science_products_land_cover_change_index Class Table

Value Color Description
1 #005f00

no change

2 #0000ff

water change

3 #eb82eb

urban change

4 #79ffd2

wetland within class change

5 #009ede

herbaceous wetland change

6 #ffd000

agriculture within class change

7 #9f2828

cultivated crop change

8 #ffff00

hay/pasture change

9 #dfdfc2

rangeland herbaceous and shrub change

10 #b3ac9f

barren change

11 #79ff00

forest change

12 #ff0000

woody wetland change

13 #ffffff

snow change

science_products_land_cover_science_product Class Table

Value Color Description
11 #466b9f

Open Water

12 #d1def8

Perennial Snow/Ice

21 #dec5c5

Developed, Open Space

22 #d99282

Developed, Low Intensity

23 #eb0000

Developed, Medium Intensity

24 #ab0000

Developed, High Intensity

31 #b3ac9f

Barren Land

41 #68ab5f

Deciduous Forest

42 #1c5f2c

Evergreen Forest

43 #b5c58f

Mixed Forest

45 #79ffd2

Shrub-Forest

46 #9f1feb

Herbaceous-Forest

52 #ccb879

Shrub/Scrub

71 #dfdfc2

Herbaceous

81 #dcd939

Hay/Pasture

82 #ab6c28

Cultivated Crops

90 #b8d9eb

Woody Wetlands

95 #6c9fb8

Emergent Herbaceous Wetlands

science_products_forest_disturbance_date Class Table

Value Color Description
83 #0000ff

non-forest or forest before 1983

84 #0033ff

forest disturbed before/at 1984

85 #005fff

forest disturbed before/at 1985

86 #0087ff

forest disturbed before/at 1986

87 #00aaff

forest disturbed before/at 1987

88 #00c5ff

forest disturbed before/at 1988

89 #00dcff

forest disturbed before/at 1989

90 #00ecff

forest disturbed before/at 1990

91 #00f8ff

forest disturbed before/at 1991

92 #00fdff

forest disturbed before/at 1992

93 #00fffd

forest disturbed before/at 1993

94 #00fff8

forest disturbed before/at 1994

95 #00ffec

forest disturbed before/at 1995

96 #00ffdc

forest disturbed before/at 1996

97 #00ffc5

forest disturbed before/at 1997

98 #00ffaa

forest disturbed before/at 1998

99 #00ff87

forest disturbed before/at 1999

100 #00ff5f

forest disturbed before/at 2000

101 #00ff33

forest disturbed before/at 2001

102 #00ff00

forest disturbed before/at 2002

103 #33ff00

forest disturbed before/at 2003

104 #5fff00

forest disturbed before/at 2004

105 #87ff00

forest disturbed before/at 2005

106 #aaff00

forest disturbed before/at 2006

107 #c5ff00

forest disturbed before/at 2007

108 #dcff00

forest disturbed before/at 2008

109 #ecff00

forest disturbed before/at 2009

110 #f8ff00

forest disturbed before/at 2010

111 #fdff00

forest disturbed before/at 2011

112 #fffd00

forest disturbed before/at 2012

113 #fff800

forest disturbed before/at 2013

114 #ffec00

forest disturbed before/at 2014

115 #ffdc00

forest disturbed before/at 2015

116 #ffc500

forest disturbed before/at 2016

117 #ffaa00

forest disturbed before/at 2017

118 #ff8700

forest disturbed before/at 2018

119 #ff5f00

forest disturbed before/at 2019

120 #ff3300

forest disturbed before/at 2020

121 #ff0000

forest disturbed before/at 2021

200 #ffffff

forest no change

Image Properties

Image Properties

Name Type Description
landcover_class_names DOUBLE

Landcover class names

landcover_class_palette DOUBLE

Landcover class palette

landcover_class_values DOUBLE

Landcover class values

impervious_descriptor_class_names DOUBLE

Impervious descriptor class names

impervious_descriptor_class_palette DOUBLE

Impervious descriptor class palette

impervious_descriptor_class_values DOUBLE

Impervious descriptor class values

Terms of Use

Terms of Use

Most U.S. Geological Survey (USGS) information is federally created data and therefore reside in the public domain and may be used, transferred, or reproduced without copyright restriction. Additional information on Acknowledging or Crediting USGS as Information Source is available.

This work was authored as part of the Contributor's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law. This is an Open Access article that has been identified as being free of known restrictions under copyright law, including all related and neighboring rights (https://creativecommons.org/publicdomain/mark/1.0/). You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.

Citations

Citations:
  • Dewitz, J., 2023, National Land Cover Database (NLCD) 2021 Products: U.S. Geological Survey data release, doi:10.5066/P9JZ7AO3

DOIs

Explore with Earth Engine

Code Editor (JavaScript)

// Import the NLCD collection.
var dataset = ee.ImageCollection('USGS/NLCD_RELEASES/2021_REL/NLCD');

// The collection contains images for the 2021 year release and the full suite
// of products.
print('Products:', dataset.aggregate_array('system:index'));

// Filter the collection to the 2021 product.
var nlcd2021 = dataset.filter(ee.Filter.eq('system:index', '2021')).first();

// Each product has multiple bands for describing aspects of land cover.
print('Bands:', nlcd2021.bandNames());

// Select the land cover band.
var landcover = nlcd2021.select('landcover');

// Display land cover on the map.
Map.setCenter(-95, 38, 5);
Map.addLayer(landcover, null, 'Landcover');
Open in Code Editor