Query for Locations Bound by a Polygon

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Before You Begin
Procedure
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You can query for location data within the perimeter of a specified polygon.

To query for location data within a perimeter, use the $geoWithin operator and specify the coordinates of the polygon's vertices:

db.<collection>.find( {
   <location field> : {
      $geoWithin : {
         $geometry : {
            type : "Polygon",
            coordinates : [ <coordinates> ]
         }
       }
    }
 } )

About this Task

The values in the field you query with the $geoWithin operator must be in GeoJSON format.
When you specify longitude and latitude coordinates, list the longitude first, and then latitude.
- Valid longitude values are between -180 and 180, both inclusive.
- Valid latitude values are between -90 and 90, both inclusive.
When you specify Polygon coordinates, the first and last coordinates in the array must be the same. This closes the bounds of the polygon.
$geoWithin does not require a geospatial index. However, a geospatial index improves query performance. Only the 2dsphere geospatial index supports $geoWithin. For more information see Create a 2dsphere Index.

Before You Begin

Create a places collection that contains these documents:

db.places.insertMany( [
   {
      loc: { type: "Point", coordinates: [ -73.97, 40.77 ] },
      name: "Central Park",
      category : "Park"
   },
   {
      loc: { type: "Point", coordinates: [ -73.88, 40.78 ] },
      name: "La Guardia Airport",
      category: "Airport"
   },
   {
      loc: { type: "Point", coordinates: [ -1.83, 51.18 ] },
      name: "Stonehenge",
      category : "Monument"
   }
] )

Procedure

Use $geoWithin to query the collection. The following $geoWithin query specifies a polygon with four vertices (a rectangle) and returns points within that polygon:

db.places.find( {
   loc: {
      $geoWithin: {
         $geometry: {
            type: "Polygon",
            coordinates: [ [
               [ -73.95, 40.80 ],
               [ -73.94, 40.79 ],
               [ -73.97, 40.76 ],
               [ -73.98, 40.76 ],
               [ -73.95, 40.80 ]
            ] ]
          }
      }
   }
} )

Output:

[
  {
    _id: ObjectId("63a4a8d67348ebdcd0a061f0"),
    loc: { type: 'Point', coordinates: [ -73.97, 40.77 ] },
    name: 'Central Park',
    category: 'Park'
  }
]

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