MongoDB Documentation, Release 3.0.4 Query Operations Geospatial Indexes Geospatial Indexes and Sharding MongoDB’s geospatial query operators let you query for: Inclusion MongoDB can query for locations contained entirely within a specified polygon. Inclusion queries use the $geoWithin operator. Both 2d and 2dsphere indexes can support inclusion queries. MongoDB does not require an index for inclusion queries; however, such indexes will improve query performance. Intersection MongoDB can query for locations that intersect with a specified geometry. These queries apply only to data on a spherical surface. These queries use the $geoIntersects operator. Only 2dsphere indexes support intersection. Proximity MongoDB can query for the points nearest to another point. Proximity queries use the $near operator. The $near operator requires a 2d or 2dsphere index. MongoDB provides the following geospatial index types to support the geospatial queries. 2dsphere 2dsphere (page 496) indexes support: New in version 2.4: 2dsphere indexes are not available before version 2.4. Query a 2dsphere Index (page 531) Query a 2d Index (page 534) 2d 2d (page 497) indexes support: You cannot use a geospatial index as the shard key index. You can create and maintain a geospatial index on a sharded collection if it uses fields other than the shard key fields. 8.2. Index Concepts 495 See also: See also: • Calculations on a sphere • GeoJSON objects and include backwards compatibility for legacy coordinate pairs • Compound indexes with scalar index fields (i.e. ascending or descending) as a prefix or suffix of the 2dsphere index field • Calculations using flat geometry • Legacy coordinate pairs (i.e., geospatial points on a flat coordinate system) • Compound indexes with only one additional field, as a suffix of the 2d index field