Question

I’m using http://maps.google.com/maps/geo? web service to geocode some addresses.

The problem I have is that a fuller address doesn’t necessarily give a more accurate geocode.

e.g passing in Llantysilio, Denbighshire, UK is far more accurate than Llantysilio, Llangollen, Denbighshire, UK

The Accuracy attribute in the XML doesn’t seem very helpful in deciding which address to pick.

How have other people dealt with this issue? Is there a good way to pick the best geocode that works most/all of the time?

*edit
A bit of extra info – when I put in the fuller address the first line of the address is ignored and the geocoder jumps to a different, but exact, address which is a central street located in the extra line added to the address. In this example, it picks Castle Street in the middle llangollen, seemingly disregarding Llantysilio.

Edit by kdgregory: here are the two API requests that I used (missing API key doesn’t seem to be an issue):

http://maps.google.com/maps/geo?q=Llantysilio,+Denbighshire,+UK&sensor=false&output=xml

http://maps.google.com/maps/geo?q=Llantysilio,Llangollen,++Denbighshire,+UK&sensor=false&output=xml

Answer 1

In the end I concluded that there are far too many weird blips in address consistency with google’s geocoding webservice in the UK, but eventually managed to figure out a way of using postcodes instead, which is far more accurate: how it’s done