Can't extract geo keys' even though the GeoJSON is valid

Question

I have a collection in MongoDB with a 2dsphere index. The object I want to save looks like this:

{
        "type" : "Polygon",
        "coordinates" : [ 
            [ 
                [ 
                    5.052617929724351, 
                    52.64653192570052
                ], 
                [ 
                    5.051738165167465, 
                    52.64765805672784
                ], 
                [ 
                    5.054162882116928, 
                    52.64831549553909
                ], 
                [ 
                    5.054592035559312, 
                    52.64780777138566
                ], 
                [ 
                    5.055364511755601, 
                    52.64790541110375
                ], 
                [ 
                    5.056094072607651, 
                    52.64688343792051
                ], 
                [ 
                    5.054237983969346, 
                    52.64661654927096
                ], 
                [ 
                    5.052617929724351, 
                    52.64653192570052
                ]
            ]
        ]
    }

According to http://geojsonlint.com/ this is perfectly valid GeoJSON. However MongoDB says it can't extract the geo keys because the GeoJSON might be malformed.

Can anyone help me out and spot the mistake?

This is the MongoDB error I get:

insertDocument :: caused by :: 16755 Can't extract geo keys from object, malformed geometry?

You have 2 arrays brackets around your point arrays. Try removing one set of the array brackets. Should be [[lat, long],[lat, long],...] — Brian Shamblen, Mar 22 '15 at 20:22
Hello Brian, I don't think this is correct. A Polygon in GeoJSON is an array of coordinate rings. GeoJSON lint also reports that this is invalid GeoJSON. I'll give it a try in MongoDB though. — Mathyn, Mar 23 '15 at 07:17
Sorry. I thought only MultiPolygon needed the extra array brackets. So funny... I found a post with the answer that started the same exact way https://groups.google.com/forum/m/#!topic/mongodb-user/OPouYFHS_zU — Brian Shamblen, Mar 23 '15 at 13:45
that's not the issue at all, this exact document works just find as a *value* of a geoJSON object in your document. — Asya Kamsky, Mar 15 '17 at 20:38
put a bounty on it because I was running into a similar situation, but my problem ended up being that the polygon did not have a matching first and last point, which doesn't appear to be the problem here, I was however getting the same error. — lyjackal, Mar 20 '17 at 17:52

score 4 · Answer 1 · edited Mar 20 '17 at 15:35

4

The problem is that you are not providing the name of the top level object that the GeoJSON would be assigned to.

You must have created the "2dsphere" index on the "coordinates" field. Instead you want to create it on the field that this entire GeoJSON value will be assigned to.

db.geo.createIndex({"location":"2dsphere"})
db.geo.insert({"location" : {
     "type" : "Polygon",
     "coordinates" : [
        [ <list of your-coord-pairs> ]
     ]
 }})
WriteResult({ "nInserted" : 1 })

edited Mar 20 '17 at 15:35

styvane

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answered Mar 15 '17 at 20:37

Asya Kamsky

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It's certainly possible this was the problem. Sadly I can no longer validate because I don't have the specific code anymore which caused the problem. – Mathyn Mar 16 '17 at 10:35
2

Apparently someone has exact same issue since they put a bounty on the answer. – Asya Kamsky Mar 16 '17 at 12:40

Can't extract geo keys' even though the GeoJSON is valid

1 Answers1