NLCD Data
Michele Claibourn, Helena Lindsay
9/11/2021
Data Source
The data represented here comes form the U.S. Geological Survey National Land Cover Database, as downloaded through the Multi-Resolution Land Characteristics consortium, https://www.mrlc.gov/
Download urls:
- NLCD 2019 Land Cover: The National Land Cover Database (NLCD) provides nationwide data on land cover and land cover change at a 30m resolution with a 16-class legend based on a modified Anderson Level II classification system. Download: https://s3-us-west-2.amazonaws.com/mrlc/nlcd_2019_land_cover_l48_20210604.zip
- NLCD 2019 Impervious Surfaces: NLCD imperviousness products represent urban impervious surfaces as a percentage of developed surface over every 30-meter pixel in the United States. Download: https://s3-us-west-2.amazonaws.com/mrlc/nlcd_2019_impervious_l48_20210604.zip
- NLCD 2016 Tree Canopy: NLCD tree canopy cover is a 30 m raster geospatial dataset containing percent tree canopy estimates, as a continuous variable, for each pixel across all land covers and types and are generated by the United States Forest Service (USFS). Download: https://s3-us-west-2.amazonaws.com/mrlc/nlcd_2016_treecanopy_2019_08_31.zip
The NLCD 2019 Tree Canopy has not yet been released, but is scheduled. The NLCD products have been updated every 2-3 years.
Variable Descriptions and Summaries
Variables include:
## Rows: 50
## Columns: 9
## $ GEOID <chr> "51109950202", "51109950300", "51079030200", "51079030102"…
## $ tree_can <dbl> 59.46266, 56.50907, 47.86960, 69.19865, 48.20600, 72.63061…
## $ imp_surf <dbl> 1.3505985, 1.2619431, 3.4312926, 0.7552143, 27.0610300, 0.…
## $ tract <dbl> 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,…
## $ cells <dbl> 153392, 379968, 98592, 184398, 6505, 249703, 105643, 66478…
## $ developed <dbl> 12972, 29060, 15873, 14967, 4070, 15079, 10272, 7045, 9804…
## $ forest <dbl> 88899, 228092, 49954, 131725, 1794, 181951, 70307, 35073, …
## $ percent_dev <dbl> 8.456764, 7.648012, 16.099684, 8.116682, 62.567256, 6.0387…
## $ percent_for <dbl> 57.955434, 60.029266, 50.667397, 71.435157, 27.578786, 72.…- GEOID: geographic identifer for spatial area (tracts, block groups, and blocks)
- tree_can: estimated percent of spatial area with tree canopy
- imp_surf: estimated percent of spatial area with impervious surface material
- cells: number of 30m cells contained in the spatial area
- developed: number of 30m cells in a spatial unit classified as developed areas
- forest: number of 30m cells in a spatial unit classified as forest areas
- percent_dev: percent of 30m cells in a spatial unit classified as developed areas
5-number summaries of variables by blocks:
##
## Summary Statistics
## ========================================
## Statistic Mean St. Dev. Min Median Max
## ----------------------------------------
## tree_can 45 29 0 48 100
## imp_surf 12 20 0 2 99
## percent_dev 37 38 0 18 100
## percent_for 37 33 0 33 100
## ----------------------------------------Visual Distributions
Tracts
Block Groups
Blocks
Maps
Land Cover
Among the 11 land cover classifications, only 8 were present in the Charlottesville region. We summed the number of 30-meter cells within a spatial unit (census tract, census block group, census block) for the most frequent classifications:
- Developed areas – developed-open, developed-low intenity, developed-medium intensity, developed-high intensity – to generate the percent of developed land
- Forest areas – deciduous forest, evergreen forest, mixed forest – to generate the percent of forested land
Tracts
Block Groups
Blocks
Block level maps are slow to render and may be added later.
Impervious Surfaces
The percent of space in each 30-meter cell covered by impervious surfaces is estimated. The measures below take the average percent of impervious surface across all of the cells within a spatial unit (census tract, census block group, census block).
Tracts
Block Groups
Blocks
Block level maps are slow to render and may be added later.
Tree Canopy
The percent of space in each 30-meter cell covered by tree canopy is estimated. The measures below take the average percent of tree canopy across all of the cells within a spatial unit (census tract, census block group, census block).
Tracts
Block Groups
Blocks
Block level maps are slow to render and may be added later.