I’m currently planning a social app in Rails that relies on being able
see how far you are from everyone else.
It’s my intention to store rough geo-coordinates as part of the sign up
process. My intention is to capture their zipcode or postal code, and
be able to query a webservice once for that data. It’s also possible
there might be a database or even a CSV somewhere that contains this
information for every zip/postalcode…
I don’t want to reinvent the wheel. The geocode APIs that I’ve seen seem
be slow and US-only. Yet dozens of sites give me quasi-accurate “your
1251 miles from Bob” type metrics - and it works across continents. How
they do this?