EarthLocation.of_address now fails because Google maps API requires a key

As of June 2018, the Google maps API requires a dev key. This breaks EarthLocation.of_address.

[pllim]

It is not good practice to publish the key, so if the env variable is publicly accessible when added to CI, please don’t do it. And to obtain the key, it needs to be associated to a Google Account (I guess you can use any existing project Gmail for that). I agree with @eteq that testing with the key is not worth the trouble.

[eteq]

I like @astrofrog’s suggestion of defaulting to OSM: https://wiki.openstreetmap.org/wiki/Nominatim has the info on that. From that you can do e.g.: https://nominatim.openstreetmap.org/search.php?q=3700+san+martin+dr%2C+baltimore%2C+md&format=json, and the first result indeed turns out to be the correct one (STScI). The JSON is not too different from what google provides so it Should Be A Quick Fix™️.

So I’d propose the following as a solution:

1. default to OSM
2. @pllim’s suggestion of introducing a google_key keyword to get back the old behavior. The docstring can provide links to the google developer console and instructions on how to get that. Not sure how to implement this in the tests, but probably just not worth it at this point?