Is there a free CDN (content delivery network) serving US Census shapefiles? Specifically, I need state legislative district boundaries.

Of course, I've googled around, and didn't see anything. Sometimes it's just a matter of knowing the right terms to search for though. I'm using them in a JavaScript-powered mapping application (Leaflet).

I must emphasize here that I don't want to link directly to the Census Bureau because AFAIK it's not an intended mode of use; they may change URLs, and probably are not set up to support heavy load. (I don't expect huge use, but you never know.)

  • Open States serves up shapefiles, and I think govtrack too, though I'm not 100% on that. Unfortunately, since Sunlight Labs shut down, Open States is in transition at the moment. Eventually, it will be up and running again. – albert Nov 23 '16 at 17:37
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    @albert Thanks, but OpenStates serves up boundaries one district at a time, which will be way too slow - I need a whole state. govtrack does Congress, not state legislatures. – Ed Staub Nov 23 '16 at 18:30
  • ...roll your own? if you don't want them on your server, github? – albert Nov 23 '16 at 18:39
  • @albert Thanks, that was plan B, of course. I think take Kotebiya's word (see accepted answer) and just assume the census should deal with it - at least for now. – Ed Staub Nov 23 '16 at 19:04
  • doh! i coulda told you about that one. no worries, glad you found your answer – albert Nov 23 '16 at 20:02

The U.S. Census Bureau is relied upon across the country for economics, demographics, research, and planning purposes. It builds itself to be used in many ways. It already handles a high load of traffic (The ACS which handles can be completed online for millions of survey respondents). Future endeavors of the Census Bureau aspire to handle loads of traffic that will break records of activity (e.g. the 2020 Census which will be online). It shouldn't be a problem to direct traffic to the Census Bureau. If anything, it will be probably help to justify their expenses.

That being said, you can find an FTP directory here which houses shapefiles at many various levels of administration which includes, for example, lower chamber legislative state boundaries and upper chamber legislative state boundaries.

  • I tried it, didn't like it, so I unaccepted. The state legislative district boundaries fail from CORS, and the tiger files you pointed at are 5x bigger. AFAICT, I'll just have to roll my own. – Ed Staub Nov 23 '16 at 20:09
  • What is your criteria for "success" and "failure"? The TIGER shapefiles are designed as the administrative boundaries, the cartographic shapefiles are the TIGER shapefiles minus major bodies of water such as the Pacific Ocean, Atlantic Ocean, or the Great Lakes. – Kotebiya Nov 23 '16 at 20:27
  • I need the smaller shapefiles, to keep the load times and memory usage down for browsers. Sizes are <1.7M, vs <10M for TIGERs. I'll probably end up hosting them myself somehow. – Ed Staub Nov 23 '16 at 21:17
  • You might also try poking around in the directory for cartographic shapefiles. There are options to use shapefiles or kml files. – Kotebiya Nov 23 '16 at 21:59
  • Yes, those are the ones, but since they're http and the census doesn't open them for cross-domain access, they're blocked by CORS. FTP isn't a good idea for a few reasons: some places have port 21 blocked, and I don't think browsers will cache it. These all lead to wanting to find a real CDN, or rolling my own. Thanks anyway, though! – Ed Staub Nov 24 '16 at 4:22

If you are looking for the state leve boundaries, Michigan provides theirs through the MIGDL. http://gis.michigan.opendata.arcgis.com/

  • Thanks, but I need all 50. 52, preferably (DC and PR). – Ed Staub Nov 23 '16 at 18:33

Or https://www.census.gov/geo/maps-data/data/tiger-geodatabases.html

The census.gov tiger geodatabases have the political boundaries.

  • Yes, I know. I explained why I don't want to point a lot of browsers at the Census bureau above. – Ed Staub Nov 23 '16 at 18:32

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