I'm building an iPhone app that often ends up in a point that is in the middle of the ocean. I want to be able to find the nearest landmasses, which in some casses are thousands of miles away.
So far I've thought of calling the maps API on the regions NW, NE, SW, SE - i.e. the ocean coordinate +10 lat, +10 long etc. until I come up with a response that isn't ZERO_RESULTS (I could obviously keep expanding the bounding box until I found something). I'm currently trying to find info on the antipode to San Francisco, which is approximately -37, 56.
The clear limitation on this is that it is in no way scalable, since Google has a request limit of 2,500 per day and I would probably be making 4+ of them per entry by a user (and I expect a user to make at least a few of these requests per use).