CODEWITHSUNDEEP
mongodbpymongomongodb-querymongoengine
J-bob
J-bob

Reputation: 9106

trouble with mongoengine and geospatial query

I'm having trouble getting Mongoengine's geospatial query to work. I've got a User mongoengine class with with a field called cached.geoLoc which is of the mongoengine type PointField(). If I call 

User.objects(cached__geoLoc__near=[100,100])

Then it returns answers. But if I want to restrict the results to a limited radius and call:

User.objects(cached__geoLoc__near=[100,100], cached__geoLoc__max_distance=1000)

then I get an error: pymongo.errors.OperationFailure: database error: Can't canonicalize query: BadValue geo near accepts just one argument when querying for a GeoJSON point. Extra field found: $maxDistance: 1000

I'm using MongoEngine version 0.8.7 and MongoDB 2.4 What could be the problem?

Upvotes: 0

Views: 1146

Answers (1)

Neil Lunn
Neil Lunn

Reputation: 151112

I'm screaming bug here.

If I try this on a similar set of data with something like the following:

class Geo(Document):
  loc = PointField()


result = Geo.objects(loc__near=[3,6], loc__max_distance=1000)

Then the resulting query issued to MongoDB is this:

{ 
    "loc" : { 
        "$near" : { 
            "$geometry" : { 
                "type" : "Point", 
                "coordinates" : [ 3, 6 ] 
             }
        }, 
        "$maxDistance" : 1000
    }
}

With the problem being the $maxDistance modifier being in the wrong place.

The correct query form issued using the raw pymongo driver commands works fine:

result = Geo._get_collection().find({
    "loc": {
        "$near": {
          "$geometry": {
            "type": "Point",
            "coordinates": [3,6]
          },
          "$maxDistance": 1000
        }
    }
}):

And mostly because we are issuing the $maxDistance modifier where it should be which is "within" the $near operator arguments.

File a bug. But you can use the direct syntax to get results as a work-around until there is a fix.

Upvotes: 2

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