如何使用mongoid，rails和谷歌地图搜索“附近用户”

Question

我有一个模型用户使用MongoDB存储的纬度和经度数据。

我正在使用google maps javascript api v3来获取此数据。

什么是显示“附近用户”的最佳方式？

Answer 1

虽然DhruvPathak答案是正确的，这里是做地理相当于mongoid Ruby代码查询

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

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

Answer 2

存储您的数据，以便它可以具有地理空间索引。 MongoDb对此有内置支持。然后，您可以轻松地使用内置的查询距离/邻近距离 。

看一看：

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)*