Sunlight reaches the pale flesh of CAGIS

November 11th, 2014

I was shocked to discover today, thanks to Jskinner at, that the Cininnati Area GIS (CAGIS) seems to have released a large and important subset of their data to the public.


I really am shocked…

Just last year I had a fairly long email exchange with some CAGIS folks, including eventually a City of Cincinnati lawyer, who insisted that the data which they collect with public dollars for civil uses was not a ‘public record’ per Ohio state law. They gave no justification for that claim of course, but I didn’t, as they well knew, have the time or money to take them to court. But anyway…if they want to start playing nice and sharing some of their toys, I’m willing to let bygones be bygones.

So what’s in there? There are two files, the larger of which (‘annual release’) you probably don’t need to bother with. The smaller file (‘quarterly release’) has some real goodies which I’ll describe below. I say that you don’t need to bother with the larger file because it looks like it only has data which could be derived from public domain federal sources like the Census and the USGS. Those sources cover the whole US and are readily available, so why trust CAGIS employees to mediate when you can go straight to the source?

Here’s what’s in the ‘quarterly release’ file(with some notes of my own):

There are a few other datasets in there, but they’re either very obscure (survey benchmarks) or redundant (parcel ‘pages’) to other datasets.  As far as I can make out, each of the files is projected in the Ohio Southern State Plane, EPSG 3735, though some of them appear to be missing that metadata.

Again, here’s the link to the data. Go nuts!

2 responses to “Sunlight reaches the pale flesh of CAGIS”

  1. IANAREA (I am not a real estate agent) but…

    Property developers likely care about the subdivision layer inasmuch as individual homeowners care about the parcel layer. This comes up quite a bit in the suburbs, where farms are still being turned into residential developments. What most folks think of as a “subdivision”¹ usually consists of multiple legal subdivisions corresponding to the farms or homesteads that got bought up. The boundaries may date to when these properties were originally platted.

    There’s also an address layer that’s probably better than anything you could get from the Census Bureau (and certainly cheaper than anything you can get from the USPS).


    1. With an HOA and a silly name like “The Oaks at Willowcreek Estates”²

    2. The oaks and willows both having been felled some years ago.

  2. Anthony Pankala says:

    Why download their data when you can just access their data on the fly by connecting to there GIS database,