Introduction and Rationale:

Due to our increasing understanding of the role the surrounding landscape plays in ecological processes, a detailed characterization of land cover, including both agricultural and natural habitats, is ever more important for both researchers and conservation practitioners. Unfortunately, in the United States, different types of land cover data are split across thematic datasets that emphasize agricultural or natural vegetation, but not both. To address this data gap and reduce duplicative efforts in geospatial processing, we merged two major datasets, the LANDFIRE National Vegetation Classification (NVC) and USDA-NASS Cropland Data Layer (CDL), to produce an integrated land cover map. Our workflow leveraged strengths of the NVC and the CDL to produce detailed rasters comprising both agricultural and natural land-cover classes. We generated these maps for each year from 2012-2021 for the conterminous United States, quantified agreement between input layers and accuracy of our merged product, and published the complete workflow necessary to update these data. In our validation analyses, we found that approximately 5.5% of NVC agricultural pixels conflicted with the CDL, but we resolved a majority of these conflicts based on surrounding agricultural land, leaving only 0.6% of agricultural pixels unresolved in our merged product.

Contents:

Spatial data

1. Attribute table for merged rasters

Technical validation data

1. Number and proportion of mismatched pixels
2. Number and proportion of unresolved pixels
3. Producer's and User's accuracy values and coverage of reference data
   Resources in this dataset:
   

   • Resource Title: Attribute table for merged rasters.

     File Name: CombinedRasterAttributeTable_CDLNVC.csv

     Resource Description: Raster attribute table for merged raster product. Class names and recommended color map were taken from USDA-NASS Cropland Data Layer and LANDFIRE National Vegetation Classification. Class values are also identical to source data, except classes from the CDL are now negative values to avoid overlapping NVC values.

   
   

   • Resource Title: Number and proportion of mismatched pixels.

     File Name: pixel_mismatch_byyear_bycounty.csv

     Resource Description: Number and proportion of pixels that were mismatched between the Cropland Data Layer and National Vegetation Classification, per year from 2012-2021, per county in the conterminous United States.

   
   

   • Resource Title: Number and proportion of unresolved pixels.

     File Name: unresolved_conflict_byyear_bycounty.csv

     Resource Description: Number and proportion of unresolved pixels in the final merged rasters, per year from 2012-2021, per county in the conterminous United States. Unresolved pixels are a result of mismatched pixels that we could not resolve based on surrounding agricultural land (no agriculture with 90m radius).

   
   

   • Resource Title: Producer's and User's accuracy values and coverage of reference data.

     File Name: accuracy_datacoverage_byyear_bycounty.csv

     Resource Description: Producer's and User's accuracy values and coverage of reference data, per year from 2012-2021, per county in the conterminous United States. We defined coverage of reference data as the proportional area of land cover classes that were included in the reference data published by USDA-NASS and LANDFIRE for the Cropland Data Layer and National Vegetation Classification, respectively. CDL and NVC classes with reference data also had published accuracy statistics.

   
   

   • Resource Title: Data Dictionary.

     File Name: Data_Dictionary_RasterMerge.csv