Question

Per title – I am using the official mongodb driver and I am looking to get all POIs within the given bounding box.

So far I have:

MongoCollection<BsonDocument> collection = _MongoDatabase.GetCollection("pois");

BsonArray lowerLeftDoc = new BsonArray(new[] { lowerLeft.Lon, lowerLeft.Lat});
BsonArray upperRightDoc = new BsonArray(new[] { upperRight.Lon, upperRight.Lat});

BsonDocument locDoc = new BsonDocument 
{
   { "$within", new BsonArray(new[] { lowerLeftDoc, upperRightDoc})}
};

BsonDocument queryDoc = new BsonDocument { { "loc", locDoc }};

IList<TrafficUpdate> updates = new List<TrafficUpdate>();
var results = collection.Find(new QueryDocument(queryDoc)).SetLimit(limit);
foreach (BsonDocument t in results)
{
} 

Unfortunatelly this doesnt work. I get:

QueryFailure flag was unknown $within type: 0 (response was { “$err” :
“unknown $within type: 0”, “code” : 13058 }).

Answer 1

The problem in your code is that you didnt specify which geo operation you wanted to use. You only specified $within but missed where. you must specify $within along with $box (bounding box) , $polygon , $center or $centerSphere / $nearSphere.

This is the correct mongo syntax to run $box queries

> box = [[40.73083, -73.99756], [40.741404,  -73.988135]]
> db.places.find({"loc" : {"$within" : {"$box" : box}}})

i am not sure about the c# mongodb syntax. But if you include ‘$box’, it ll work