CODEWITHSUNDEEP
springmongodbmongodb-querygeospatial
Minky
Minky

Reputation: 121

Mongo DB: no result found when using $near query

I am using Mongo DB to store coordinates and I want to find coordinates using $near query, but I got no result, can anybody help me? Here is my index of mongo db

> db.course.getIndexes()
[
    {
            "v" : 1,
            "key" : {
                    "_id" : 1
            },
            "name" : "_id_",
            "ns" : "dev.course"
    },
    {
            "v" : 1,
            "key" : {
                    "coordinate" : "2dsphere"
            },
            "name" : "coordinate_2dsphere",
            "ns" : "dev.course",
            "2dsphereIndexVersion" : 3
    }
]

Here is my data

{ "_id" : 1,  "schoolId" : 0, "longitude" : 0, "latitude" : 0, "coordinate" : [ 0, 0 ], "courseTitle" : "暂无", "imageIds" : "[]", "videoIds" : "[]", "startTime" : "", "teacherIds" : "[]", "gradeIds" : "[]", "subjectId" : 0, "expense" : 0, "followNum" : 0, "courseStatus" : "NOSTART", "authorizationStatus" : "NO", "rejectReason" : "", "createTime" : "2017-01-01 16:58:22" }

My query is 

db.course.find({"coordinate": {"near": [123, 20]}})

There is no result. Can anybody help me?

Upvotes: 0

Views: 183

Answers (1)

Bertrand Martel
Bertrand Martel

Reputation: 45352

$near is the operator to use, if you write near it will only match a field named near under coordinate field.

The $near request would be like : 

db.course.find({
    "coordinate": {
        "$near": {
            $geometry: {
                type: "Point",
                coordinates: [123, 20]
            }
        }
    }
})

To use 2dsphere index the document should be of GeoJSON format which needs an additionnal type field : 

{ type: "<GeoJSON type>" , coordinates: <coordinates> }

So you just need to replace "coordinate" : [ 0, 0 ] with :

"coordinate": {
    type: "Point",
    coordinates: [0, 0]
}

Upvotes: 1

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