$maxDistance

The $maxDistance operator specifies an upper bound to limit the results of a geolocation query. See below, where the $maxDistance operator narrows the results of the $near query:

db.collection.find( { location: { $near: [100,100], $maxDistance: 10 } } );

This query will return documents with location fields from collection that have values with a distance of 5 or fewer units from the point [100,100]. $near returns results ordered by their distance from [100,100]. This operation will return the first 100 results unless you modify the query with the cursor.limit() method.

Specify the value of the $maxDistance argument in the same units as the document coordinate system.

在 2.2.3 版更改: Before 2.2.3, a geospatial index must exist on a field holding coordinates before using any of the geolocation query operators. After 2.2.3, applications may use geolocation query operators without having a geospatial index; however, geospatial indexes will support much faster geospatial queries than the unindexed equivalents.