MongoDb Polygon Search Query returns no result

Question

I have problems regarding a Polygone Search in my MongoDB.

I have a document structure like:

Object:{id,type,...,
    data:{
    name,
    loc:{
    lng:xxx
    lat:yyy
    type:Point}}}

I have an 2d Index on "data.loc".

My query in java code is:

DBCollection coll = database.getCollection(type);

    BasicDBList points = new BasicDBList();
    points.add(bbox.getNe());
    points.add(bbox.getSe());
    points.add(bbox.getSw());
    points.add(bbox.getNw());
    points.add(bbox.getNe());
    BasicDBList parentList = new BasicDBList();
    parentList.add(points);

    DBObject query = new BasicDBObject("data.loc",
            new BasicDBObject("$geoWithin",
                    new BasicDBObject("$geometry", new BasicDBObject("type","Polygon")
                            .append("coordinates", parentList))));

The Debuger tells me that the query is for example

{ "data.loc" : { "$geoWithin" : { "$geometry" : { "type" : "Polygon" , "coordinates" : [ [ [ 48.240553 , 16.451597] , [ 48.162751 , 16.451597] , [ 48.162751 , 16.303968] , [ 48.240553 , 16.303968] , [ 48.240553 , 16.451597]]]}}}}

But after typing

DBCursor cursor = coll.find(query);

 try {
        while(cursor.hasNext()) {
            data.add(cursor.next().get("data"));
        }
 } finally {
        cursor.close();
 }

    return data;´

data is allways null.

Can anyone find any problems in my approach or does maybe someone have a better approach? In fact I want to do a boundingbox search on my database.

Thank you for your help! Best regards Daniel

Can you give an example of one of your documents that you expect to be found by the geo query? Also, to clarify, it's a 2d index and not a 2d sphere index? — wdberkeley

Shachty Shachty · Accepted Answer · 2014-12-22T13:40:23

Okay, so the Java MongoDB driver query for the points in the polygone for a GeoJson strcuture like this is

  BasicDBList points = new BasicDBList();
    points.add(bbox.getNe());
    points.add(bbox.getSe());
    points.add(bbox.getSw());
    points.add(bbox.getNw());
    points.add(bbox.getNe());
    BasicDBList parentList = new BasicDBList();
    parentList.add(points);

    Set<Object> data = new CopyOnWriteArraySet<Object>();

    DBObject query = new BasicDBObject("geometry",
            new BasicDBObject("$geoWithin",
                    new BasicDBObject("$geometry", new BasicDBObject("type","Polygon")
                            .append("coordinates", parentList))));
    System.err.println(query);

MongoDb Polygon Search Query returns no result

1 Answers