The San Diego, CA Meter Urban Land Cover (MULC) dataset was generated from sub-meter image pixel resolution data created by the University of Vermont (UVM) Spatial Analysis Laboratory (SAL) through the combined use of 2014 USDA National Agricultural Imagery Program (NAIP) four band (red, green, blue and near infrared) aerial ortho-imagery, 2014 LiDAR data covering coastal extents, 2015 LiDAR data covering inland areas, and GIS ancillary data provided by the city of San Diego or created by the UVM Spatial Analysis Laboratory under the direction of Jarlath O'Neil-Dunne. Object-based image analysis techniques (OBIA) were employed to classify a land cover product with seven land cover classes: Tree Canopy, Grass/Shrub, Bare Earth, Water, Buildings, Roads, Other Paved Surfaces.

This EPA-modified dataset was derived from the SAL seven-class land cover product. Land cover data were resampled to a 1-meter spatial resolution by EPA for MULC data product integration. Updates to the data were completed by EPA in 2020 to correct for errors or data voids in the original dataset and modified, as necessary, to meet MULC mapping product standards. The seven land cover classes mapped by SAL were condensed by EPA into five baseline land cover class categories as follows: Water, Impervious, Soil/Barren, Tree/Forest, Grass/Herbaceous. Additional corrections to the five condensed land cover classes were implemented using the five land cover classes prior to any additional land cover class category additions and final modifications.

The mapped area is confined to the boundaries of US Census Bureau's 2010 Urban Statistical Area for San Diego County, with an added 1-km buffer area around the San Diego dataset extent (with exception of areas on the southern U.S - Mexico border). A total of seven land cover classes were mapped: Water, Impervious, Soil or Barren, Trees or Forest, Grass or Herbaceous, Woody Wetlands and Emergent Wetlands.

The mapped area encompasses a total approximate area of 3,974 square kilometers and is confined to the boundaries of US Census Bureau's 2010 Urban Statistical Area for San Diego County, with an added 1-km buffer area (with exception of the data extent along the southern U.S - Mexico borderline). A total of seven land cover classes were mapped in the finalized product: Water, Impervious, Soil or Barren, Trees or Forest, Grass or Herbaceous, Woody Wetlands and Emergent Wetlands.

Integrated wetland features were derived using ancillary National Wetlands Inventory (NWI) polygon data (version 2), downloaded from the Unites States Fish and Wildlife Service (USFWS) Wetland Mapper web mapping service (https://www.fws.gov/wetlands/data/mapper.html). Metadata for the NWI wetlands data layer can be found at http://www.fws.gov/wetlands/Data/Metadata.html.

An accuracy assessment of the classified product, using 1259 combined random and stratified random photo-interpreted land cover reference sample points yielded an overall user's accuracy (MAX) of 52.0 percent and a fuzzy user's accuracy (RIGHT) of 83.4 percent.

This dataset was collaboratively developed by the University of Vermont Spatial Analysis Laboratory, the United States Forest Service Urban Tree Canopy (UTC) assessment program, and the US EPA to support research and online mapping activities related to the EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

For data workflow processing details see Overview Description section.