当试图获取MongoDB中所有记录的距离时，“找不到ns”

Question

我在Robomongo / cli中使用此查询来获取最接近给定坐标的记录，该记录正常工作。

以下是使用查找

的查询

db.places.find(
  {
    loc : {
      $near : {
        $geometry : { 
          type : "Point" , 
          coordinates : [12.974729, 77.609375]  
        }, 
        $maxDistance : 2000
      }
    }
  }
);

JSON

{
    "_id" : ObjectId("56c6becd8586e7a757260d62"),
    "name" : "address here",
    "loc" : {
        "type" : "Point",
        "coordinates" : [ 
            12.9802900000000001, 
            77.5857400000000013
        ]
    }
}
{
    "_id" : ObjectId("56d002a7ce57e202b2cd43ea"),
    "name" : "address 2",
    "loc" : {
        "type" : "Point",
        "coordinates" : [ 
            12.9751499999999993, 
            77.6248930000000001
        ]
    }
}

现在我如何获得均匀的距离。我使用以下查询但是给了我 errmsg “找不到ns”

db.runCommand( {
    geoNear: "places" ,
    near: { type: "Point", coordinates: [12.974729, 77.609375] },
    spherical: true,
    maxDistance: 2000
})