http://stackoverflow.com/questions/13652197/getting-array-elements-using-array-index-in-mongodb
http://blog.mongolab.com/2014/08/a-primer-on-geospatial-data-and-mongodb/
http://stackoverflow.com/questions/20883420/pymongo-asyncmongo-maxdistance-not-working
http://geojson.org/geojson-spec.html#id4
http://docs.mongodb.org/manual/administration/indexes-geo/
http://maps.google.com/
http://discussions.udacity.com/t/problem-loading-json-file/15793/5
http://www.openstreetmap.org/
https://wiki.openstreetmap.org/wiki/Main_Page
http://overpass-api.de/query_form.html
http://matplotlib.org/examples/pie_and_polar_charts/pie_demo_features.html