I'm not sure where you are reffering to setting my geolocation? Location is turned on in the Android settings. In the Rachio app under device settings I click on the device name (which shows Cincinnati,MI under it). That is where I can update the zip code and click the button that says update my location. When I click the "update my location" button the numbers that presumably represent longitude and latitude change slightly so I believe it's getting the location from the phones GPS.
If there is something else that I should be looking at or changing, let me know.