MongoDB geospatial difference between $near and $within

问题

What is the difference between $near and $within?

db.geodata.find({ "loc" : { "$within" : { "$center" : [ [ 12.91365 , 77.59395] , 4]}}}).limit(10);

db.geodata.find({ "loc" : { "$near" : [ 12.91365 , 77.59395] , "$maxDistance" : 4}}).limit(10); 

Can anyone explain in detail?

回答1:

The main differences are

• $near sorts based on distance from a point; $geoWithin tests for containment in a polygon or multipolygon with GeoJSON coordinates, or containment in one of a set of shapes for 2d coordinates
• $near returns document from nearest to farthest and any other order requires in-memory sorting; $geoWithin can be used with other sort indexes
• $near requires a geospatial index; $geoWithin performs better with one but does not require it
• $near is not supported in sharded clusters - you have to use the geonear command or$geoNear aggregation stage instead

Also check out the documentation for $near and $geoWithin.

来源：https://stackoverflow.com/questions/28460960/mongodb-geospatial-difference-between-near-and-within