How to search for "Nearby Users" using mongoid, rails, and google maps

I have a model User with Latitude and Longitude data stored usi开发者_如何转开发ng Mongo DB.

I'm using the google maps javascript api v3 to get this data.

What's the best way to display "Nearby Users"?

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Though DhruvPathak answer is correct, here is the equivalent mongoid ruby code for doing geo queries

User.where(:loc => {'$near' => [50,50]})

User.where(:loc => {'$near' => [50,50],'$maxDistance' => 5})

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Store your data so that it can have geospatial indexing. MongoDb has inbuilt support for this. Then you can easily use inbuilt querying for distance/proximity .

Have a look at :

http://www.mongodb.org/display/DOCS/Geospatial+Indexing

*Querying

The index can be used for exact matches:

db.places.find( { loc : [50,50] } )

Of course, that is not very interesting. More important is a query to find points near another point, but not necessarily matching exactly:

db.places.find( { loc : { $near : [50,50] } } )

The above query finds the closest points to (50,50) and returns them sorted by distance (there is no need for an additional sort parameter). Use limit() to specify a maximum number of points to return (a default limit of 100 applies if unspecified):

db.places.find( { loc : { $near : [50,50] } } ).limit(20)

You can also use $near with a maximum distance

db.places.find( { loc : { $near : [50,50] , $maxDistance : 5 } } ).limit(20)*