The US Census currently distributes two zips for ZIP Code Tabulation Areas (ZCTA) data with 33,114 features,

  • Gazetteer ZCTA (59M)

  • TIGER ZCTA (502M)


What's the difference between the Gazetteer and TIGER data? Why such a large file size difference? Which one should I use? They both have 33,144 features.

Likewise, we see that with the state dataset, Combined Statistical Areas csa, and Core Based Statisical Areas cbsa

  • Gazetteer State (4.6M)

  • TIGER State (15M)

  • Gazetteer CSA (2.5M)

  • TIGER CSA (18M)

  • Gazetteer CBSA (6.4M)

  • TIGER CBSA (50M)

  • 3
    how a geodata related question migrated from gis.stackexchange.com to here is beyond me. step up your game gis se.
    – albert
    Oct 14 '16 at 19:12

Upon closer inspection, it seems that the TIGER line zcta summary level 510 shapefile has more detail of the boundaries and the Gazetteer shapefile has simplified vertices that if I had to guess were designed to be used for map visualization at a scale of 1:500,000 or greater (hence the 500k).


I wrote to the Census and they wrote back,

The Gazetteer file you are looking at is a Cartographic Boundary Shapefile which is for small scale (limited detail) mapping projects clipped to shorelines. Designed for thematic mapping using GIS. The TIGER/Line shapefile is the most comprehensive dataset hence the difference in file size. So depending on what level of detail you need will depend on which file you use. Here is the TIGER Products link: http://www.census.gov/geo/maps-data/data/tiger.html see the graph at the bottom if you want to compare the product types.

Please let me know if I can be of further assistance.

I'm not exactly sure why anyone wouldn't just always use the TIGER database. But, for whatever reason there are two. For comparison here is a map with CBSA and CSA layered over each other. The green is CBSA, and the red-dash is CSA. The first frame, the one with more green, is the TIGER set. Note, I generated with the 2016 TIGER set and the 2015 Gazetteer set.


I'm not sure of the context of thematic, but clearly the Gazeteer CBSA zones excludes more water and the CBSA zones in TIGER include it. Also, thanks to the email and the name we can see that the Gazetteer files are also called Cartographic Boundary Shapefile. In the link provided,

Tiger Line Shapefiles are defined as,

Full detail (not generalized) ; Shapefiles (.shp) and database files (.dbf); Most mapping projects--this is our most comprehensive dataset. Designed for use with GIS (geographic information systems).

And Cartographic Boundary Shapefiles (aka Gazetteer files) are defined as,

Less detail (generalized); Shapefiles (.shp); Small scale (limited detail) mapping projects clipped to shoreline. Designed for thematic mapping using GIS.

However, looking into it further the Cartographic Boundary Shapefiles also have .dbf files.

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