R: Yahoo/Bing or other alternatives to Google Earth for geocoding?

Question

I am estimating latitudes and longitudes for 500K+ locations. The geocode() function in the dismo package appears to be perfect, but uses Google Earth as the backend. The problem is that GE has a usage limit of 2500 queries/day only, which throws dismo out for me as a realistic solution. So my questions are:

1. Is there any other package which does the same thing, but uses Yahoo, Bing or some another backend with more generous limits?
2. Is there any other way of running bulk queries outside of R which I may not be aware of? The solution must necessarily be free :-(

NOTE: I am running the queries for places in India, so a US-only solution will not do.

SUPPLEMENTARY QUESTION: I am not a developer, so I might be talking through a hat here. It seems to me that the geocode() function is calling Google's API under the hood, and is hence able to spit out the lat/long coordinates. Since r/dismo is open-source, is there any way to change the pointer to Yahoo/Bing?

Answer 1

Yahoo will allow up to 50k queries per API key per day. Bing will allow 10k. Google's limit of 2500 is based on IP address, rather than an API key. All of these have pretty strict terms of use around how the data may be used. Generally, they insist that it only be used in a display (e.g., a webpage) and may not be stored in any way. The docs are worth a read if you intend to use the services for anything other than exploratory research.

You might try the geocoding service at USC. I haven't used it myself, but it appears to allow up to 2500 requests per transaction and has both a batch service via file upload and an API.