Skip to main content

GIS Data Sources: Useful Codes

Codes used in GIS files

ANSI (formerly FIPS) Codes:  Most Census data uses filenames based on ANSI codes issued by the American National Standards Institute. These were formerly known as Federal Information Processing Standards (FIPS) codes that were published by the National Institute of Standards and Technology (NIST). The Census Bureau provides lists of ANSI codes used by them for counties and for other geographic entities (states, MSA's, Congressional Districts, etc.).

MSA's: The Office of Management and Budget (OMB) defines Metropolitan Statistical Areas (MSAs) as a group of counties that encompass the metro area.  In recent years, they have also defined some lower population areas as Micropolitan Statistical Areas.  To determine which counties make up a metro area during a particular census, the Census web site has MSA listings showing the metro areas that were in effect for decennial censuses back to 1950.  They also link to policy documents relating to the definitions.

Note: In 2000, the MSA's for large metro areas were divided into Primary Metropolitan Statistical Areas (e.g., Dallas) and Consolidated Metropolitan Statistical Areas (e.g., Dallas-Fort Worth).  Check with your instructor regarding what level to use for an assignment.  Since 2000, the OMB defined Metropolitan Divisions as subcomponents of some Metropolitan Statistical Areas. MSA's can be grouped into larger aggregations called Combined Statistical Areas (roughly equivalent to the old Consolidated MSA). Currently, the Raleigh-Durham-Cary CSA consists of the Raliegh-Cary MSA and the Durham MSA along with the Dunn Micropolitan Statistical Area.

Key to TIGER2000 Filenames: Included in any zip file from ESRI's ArcData site is a key to the filenames of the TIGER layers, to help you remember what you downloaded. These naming conventions may show up in census data from other sources, too.

Feature Class Codes (FCC's) are used byt he Census Bureau in coding features within some features, such as the various categories of streets, roads, highways, and freeways in street or road layers, and are often used in attribute tables. Knowing the meaning of these codes can help in selecting or clearly displaying features in a layer. The current version are the MAF/TIGER FCCs (MTFCC). Before 2007, Census used different codes called CFCCs.  List of MTFCCs from CensusList of CFCCs from ESRI. CFCC to MTFCC Translation Table from Census, with detailed definitions (Excel)

Land Use - Land Cover (LULC) Codes  You will need to join a dBase file to a downloaded LULC layer's attribute table in order to match English words to the numeric LULC classification codes.  (Field LUCODE in the attribute table matches to LU2-CODE in the dBase file.)  These files can be downloaded from WebGIS