Saturday, November 09, 2013

Texas A&M Geocoding services saves the day

In my inbox yesterday landed a list of 650 damaged houses from the October 31st flooding here in Central Texas. It had street address, but no zip or city. I got excited when I saw PLACE_ID, because I thought I could use that to match a parcel shapefile that I received from the county tax assessor's office.

Well, never assume. When I got to merging the files later in the day, I found that PLACE_ID is not the same as PROP_ID, and I was screwed.

I then remembered that Texas A&M GeoServices has a batch geocoding service. I'd tried it before with a smaller list, but didn't have much success for some reason I couldn't remember. So I tried again.

My original file had just a "Full Street Address" like 10000 WILD DUNES DR. I knew some were in Austin and some were not, but I just added columns for City and State and made them all Austin and ran it through the batch geocoder to see what would happen.

It took about 3 minutes process the 650 records, and it spit back all kinds of good information beyond the Lat and Long, mainly the "GeocodeQualityType." I knew from my geocoding experience with the Bastrop fires several years ago that "CityCentroid" wasn't a good result, and that was true for about a third of them. I was really looking for "ExactParcelCentroidPoint."

Since many addresses were on the similar streets, I manually added a ZIP to all the addresses and ran it through again, with *much* better results. All but one address was either "ExactParcelCentroidPoint" or "AddressRangeInterpolation" which turned out to be pretty good.

The Google Fusion Tables map is below, and this link is to the entire interactive.

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