地理位置索引-2d索引

```

> db.location.ensureIndex({"w":"2d"})

{

"createdCollectionAutomatically" : true,

"numIndexesBefore" : 1,

"numIndexesAfter" : 2,

"ok" : 1

}

> db.location.insert({w:[1,1]})

WriteResult({ "nInserted" : 1 })

> db.location.insert({w:[1,2]})

WriteResult({ "nInserted" : 1 })

> db.location.insert({w:[3,2]})

WriteResult({ "nInserted" : 1 })

> db.location.insert({w:[100,100]})

WriteResult({ "nInserted" : 1 })

> db.location.insert({w:[200,100]})

WriteResult({

"nInserted" : 0,

"writeError" : {

"code" : 13027,

"errmsg" : "point not in interval of [ -180, 180 ] :: caused by :: { _id: ObjectId('5870915a9a0bf268727ed5c0'), w: [ 200.0, 100.0 ] }"

}

})

> db.location.insert({w:[180,100]})

WriteResult({ "nInserted" : 1 })

> db.location.remove({w:[180,100]})

WriteResult({ "nRemoved" : 1 })

> db.location.insert({w:[180,80]})

WriteResult({ "nInserted" : 1 })

> db.location.find({w:{$near:[1,1]}})

{ "_id" : ObjectId("587091389a0bf268727ed5bc"), "w" : [ 1, 1 ] }

{ "_id" : ObjectId("5870913c9a0bf268727ed5bd"), "w" : [ 1, 2 ] }

{ "_id" : ObjectId("587091419a0bf268727ed5be"), "w" : [ 3, 2 ] }

{ "_id" : ObjectId("587091509a0bf268727ed5bf"), "w" : [ 100, 100 ] }

{ "_id" : ObjectId("587091979a0bf268727ed5c2"), "w" : [ 180, 80 ] }

> db.location.find({w:{$near:[1,1],$maxDistance:10}})

{ "_id" : ObjectId("587091389a0bf268727ed5bc"), "w" : [ 1, 1 ] }

{ "_id" : ObjectId("5870913c9a0bf268727ed5bd"), "w" : [ 1, 2 ] }

{ "_id" : ObjectId("587091419a0bf268727ed5be"), "w" : [ 3, 2 ] }

> db.location.find({w:{$near:[1,1],$maxDistance:10,$minDistance:1}})

{ "_id" : ObjectId("5870913c9a0bf268727ed5bd"), "w" : [ 1, 2 ] }

{ "_id" : ObjectId("587091419a0bf268727ed5be"), "w" : [ 3, 2 ] }

> db.location.find({w:{$near:[1,1],$maxDistance:10,$minDistance:2}})

{ "_id" : ObjectId("587091419a0bf268727ed5be"), "w" : [ 3, 2 ] }

> db.location.find({w:{$near:[1,1],$maxDistance:10,$minDistance:3}})

>

```