Found this interesting: MongoDB has native support for geospatial indexes and extensions to the query language to support a lot of different ways of querying your geo spatial documents. We will touch on a all of the available features of the MongoDB geospatial support point by point as including:
Query $near a point with a maximum distance around that point
Set the minimum and maximum range for the 2d space letting you map any data to the space
GeoNear command lets you return the distance from each point found
$within query lets you set a shape for you query letting you use a circle, box or arbitrary polygon, letting you map complex geo queries such as congressional districts or post code zones.
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