$ ear和$ within之间的MongoDB地理空间差异 [英] MongoDB geospatial difference between $near and $within

问题描述

$near和$within有什么区别?

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); 

任何人都可以详细解释吗?

Can anyone explain in detail?

推荐答案

主要区别是

• $near根据距点的距离进行排序； $geoWithin测试包含GeoJSON坐标的多边形或多面中的包含度，或包含2d坐标的一组形状中的包含度
• $near从最近到最远返回文档，其他任何顺序都需要在内存中排序； $geoWithin可以与其他排序索引一起使用
• $near需要地理空间索引； $geoWithin表现更好，但不需要它
分片群集不支持
• $near-您必须使用geonear命令或$geoNear聚合阶段

• $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

还要查看 $ near 和 $ geoWithin .

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