I've been using sphinx for georanking, on top of mysql. Works really well. If you're using ruby, be sure to have a look at thinking_sphinx which provides a gre

I've been using sphinx for georanking, on top of mysql. Works really well. If you're using ruby, be sure to have a look at thinking_sphinx which provides a great dsl to configure the index and query it. Also MongoDB has a built-in geographical index. I would not personnally roll my own here.