Please find attached the data documentation.
The Atlas is based on 2010 census tract polygons. To use the underlying Atlas data in a GIS, the data from this spreadsheet needs to be joined to a census tract boundary file. With ESRI software, users should have access to the tract layer on ESRI's "Data and Maps" data distribution. For users of other software, tract boundaries can be downloaded directly from the Census Bureau's Cartographic Boundary Files. The underlying map services used in the Food Access Research Atlas are also available for both developers and GIS users. See the Geospatial API documentation for more information.