maps.chandlerswift.com/layers/census-bureau/README.md

1.2 KiB

from the US Census Bureau:

https://www.census.gov/geographies/mapping-files/time-series/geo/cartographic-boundary.html

more description here:

https://www.census.gov/programs-surveys/geography/technical-documentation/naming-convention/cartographic-boundary-file.html

Including the following:

File Naming Convention

2013 to Present Files

The cartographic boundary files are named cb_yyyy_ss__rr.zip where:

  • yyyy = 4 digit year
  • ss = state FIPS code or 'us' for a national level file
  • entity = the entity name
  • rr = resolution level
    • 500k = 1:500,000
    • 5m = 1:5,000,000
    • 20m = 1:20,000,000

I prefer the KML options when available since OpenLayers doesn't [citation needed?] have built-in support for shapefiles (.shp)? That said, we also do transform KML to GeoJSON to be able to edit more easily (and it's sometimes good for a smaller file size).

For more information, see e.g.:

https://indicatrix.org/post/shapefiles-in-openlayers/

Census Bureau data appears to be using a different (US-centric, possibly?) projection; this may require more work to be accurate going forward.

https://gis.stackexchange.com/a/310949

https://epsg.io/4269