I’m writing a geocoding component for an app I’m building, and I decided to use Yahoo Maps. I wrote the geocode API wrapper and some unit tests and called it a day. Came back the next day, ran the tests, and found that the latitude and longitude had changed. Mind you, the change was small enough not to matter to me, but it was significant enough to affect the rounding to 4 decimal places that I was using in my unit test to compare the result.
I’ve never heard of changing latitude and longitude before. Is this something I should expect / account for? Can anyone explain why?
Geocoding, especially when done from addresses, is rarely 100% accurate. There are many companies who do nothing but compile the street data used for geocoding purposes.
The data is not accurate, but is frequently updated to improve address matching. When this happens, you’ll get a different result. My guess is that one of two things happened:
1) Yahoo updated their source data.
2) You got a result from a different server with a different set of source data.