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README.md
nlcdLandCover.py
reclassTable.csv

README.md

Land Cover Categories

This script produces the categorical rasters for specified land use types based on the National Land Cover Dataset. In each raster, a value of 1 represents the presence the specified land cover classification and a 0 represents the absence.

Data Sources

Layer Source
Land Use Raster National Land Cover Dataset
Catchments Conte Ecology Group - NHDHRDV2

Steps to Run:

The folder structure is set up within the scripts. In general, the existing structure in the repo should be followed. Raw data should be unzipped, but otherwise kept in the same format as it is downloaded.

  1. Open the script nlcdLandCover.py

  2. Change the values in the "Specify inputs" section of the script

  • baseDirectory is the path to the \nlcdLandCover folder
  • catchmentsFilePath is the file path to the catchments polygons shapefile (See "Notes" section)
  • rasterFilePath is the file path to the raw NLCD Land Use raster (.img format)
  • reclassTable is the file path to the table used to reclassify the raw raster into individual categorical rasters. (See current version in the \nlcdLandCover folder)
    1. A value of 1 means to include this class
    2. A value of 0 means to exclude this class
    3. A value of -9999 means this class will be converted to NA
    4. Reclassification Table Example:
Class Value forest developed devel_opn
Open Water 11 0 0 0
Perennial Ice/Snow 12 0 0 0
Developed, Open Space 21 0 1 1
Developed, Low Intensity 22 0 1 0
Developed, Medium Intensity 23 0 1 0
Developed, High Intensity 24 0 1 0
Barren Land (Rock/Sand/Clay) 31 0 0 0
  • outputName is the name that will be associated with this particular run of the tool (e.g. NHDHRDV2 for all High Resolution Catchments)
  • keepFiles specifies whether or not to keep the intermediate GIS files. Enter "NO" to delete or "YES" to keep.
  1. Run the script in ArcPython. It does the following:
  • Sets up the folder structure in the specified directory
  • Generates the processing boundary from the specified shapefile and clips the source raster to this spatial range
  • Creates the individual categorical rasters based on the reclassification table
  • Saves the completed rasters to the [baseDirectory]\gisFiles\[outputName]\outputFiles directory

Output Rasters

The number of rasters generated by this script will be equal to the number of columns (beyond the first 2) specified in the reclassification table. The rasters will receive the same name as the column name. Be sure to adhere to ArcGIS field name restrictions as well as the 13 character limit on ArcGrid file names. Currently, the created rasters are:

Percent Forest

Raster name: forest
Description: This layer represents the NLCD land cover defined as forested (where "Land_Cover" = "Deciduous Forest", "Evergreen Forest", "Mixed Forest", "Woody Wetlands", "Palustrine Forested Wetland", or "Estuarine Forested Wetland").

Percent Developed

Raster name: developed
Description: This layer represents the NLCD land cover defined as developed (where "Land_Cover" = "Developed, Open Space", "Developed, Low Intensity", "Developed, Medium Intensity", "Developed, High Intensity", "Unconsolidated Shore/Quarries/Gravel Pits/Strip Mines", or "Urban/Recreational Grasses").

Percent Developed, High Intensity

Raster name: devel_hi
Description: This layer represents the NLCD land cover defined as high intensity development (where "Land_Cover" = "Developed, High Intensity").

Percent Developed, Medium Intensity

Raster name: devel_med
Description: This layer represents the NLCD land cover defined as medium intensity development (where "Land_Cover" = "Developed, Medium Intensity").

Percent Developed, Low Intensity

Raster name: devel_low
Description: This layer represents the NLCD land cover defined as low intensity development (where "Land_Cover" = "Developed, Low Intensity").

Percent Developed, Open

Raster name: devel_opn
Description: This layer represents the NLCD land cover defined as developed land that is open space (where "Land_Cover" = "Developed, Open Space").

Percent Deciduous Forest

Raster name: forest_decid
Description: This layer represents the NLCD land cover defined as deciduous forest (where "Land_Cover" = "Deciduous Forest").

Percent Evergreen Forest

Raster name: forest_evgrn
Description: This layer represents the NLCD land cover defined as evergreen forest (where "Land_Cover" = "Evergreen Forest").

Percent Mixed Forest

Raster name: forest_mixed
Description: This layer represents the NLCD land cover defined as mixed forest, not defined in the previous two layers (where "Land_Cover" = "Mixed Forest", "Woody Wetlands", "Palustrine Forested Wetland", or "Estuarine Forested Wetland").

Percent Wetland

Raster name: wetland
Description: This layer represents the NLCD land cover defined as wetlands (where "Land_Cover" = "Woody Wetlands", "Palustrine Forested Wetland", "Palustrine Scrub/Shrub Wetland", "Estuarine Forested Wetland", "Estuarine Scrub/Shrub Wetland", "Emergent Herbaceous Wetlands", "Palustrine Emergent Wetland (Persistent)", "Estuarine Emergent Wetland", "Palustrine Aquatic Bed", or "Estuarine Aquatic Bed").

Percent Open Water

Raster name: wetland
Description: This layer represents the NLCD land cover defined as open water (where "Land_Cover" = "Open Water").

Percent Herbaceous

Raster name: herbaceous
Description: This layer represents the NLCD land cover defined as herbaceous (where "Land_Cover" = "Transitional", "Dwarf Scrub", "Shrub/Scrub", "Grassland/Herbaceous", "Sedge/Herbaceous", "Lichens", "Moss", "Urban/Recereational Grasses", "Palustrine Scrub/Shrub Wetland", "Estuarine Scrub/Shrub Wetland", "Emergent Herbaceous Wetlands", "Palustrine Emergent Wetland (Persistent)", or "Estuarine Emergent Wetland").

Percent Agriculture

Raster name: agriculture
Description: This layer represents the NLCD land cover defined as agricultural land (where "Land_Cover" = "Orchards/Vineyards", "Pasture/Hay", "Cultivated Crops - row crops", "Cultivated Crops - small grains", or "Fallow").

Percent Undeveloped Forest

Raster name: undev_forest
Description: This layer represents the NLCD land cover defined as land that is forested. (where "Land_Cover" = "Deciduous Forest", "Evergreen Forest", "Mixed Forest", "Woody Wetlands", "Palustrine Forested Wetland", "Estuarine Forested Wetland"). Additionally, land defined as being developed (where "Land_Cover" = "Developed, Open Space", "Developed, Low Intensity", "Developed, Medium Intensity", "Developed, High Intensity", "Barren Land (Rock/Sand/Clay)", and "Unconsolidated Shore/Quarries/Gravel Pits/Strip Mines") is removed from the layer and counted as NA.

Notes

  • Typically, the catchmentsFilePath variable specifies a shapefile of hydrologic catchments defining the range over which the "Zonal Statistics" tool will be applied. It is possible to enter another polygon shapefile, such as state or town boundaries, as this variable. The primary purpose of this layer is to trim the original raster, which represents the continental US, to a manageable size.

Next Steps

  • Classification definitions can be changed by editing the reclassTable.csv file.