$geoIntersects¶

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Definition
Behavior
Examples

Definition¶

$geoIntersects¶

New in version 2.4.

Selects documents whose geospatial data intersects with a specified GeoJSON object; i.e. where the intersection of the data and the specified object is non-empty. This includes cases where the data and the specified object share an edge.

The $geoIntersects operator uses the $geometry operator to specify the GeoJSON object. To specify a GeoJSON polygons or multipolygons using the default coordinate reference system (CRS), use the following syntax:

{
  <location field>: {
     $geoIntersects: {
        $geometry: {
           type: "<GeoJSON object type>" ,
           coordinates: [ <coordinates> ]
        }
     }
  }
}

For $geoIntersects queries that specify GeoJSON geometries with areas greater than a single hemisphere, the use of the default CRS results in queries for the complementary geometries.

New in version 3.0: To specify a single-ringed GeoJSON polygon with a custom MongoDB CRS, use the following prototype that specifies the custom MongoDB CRS in the $geometry expression:

{
  <location field>: {
     $geoIntersects: {
        $geometry: {
           type: "Polygon" ,
           coordinates: [ <coordinates> ],
           crs: {
              type: "name",
              properties: { name: "urn:x-mongodb:crs:strictwinding:EPSG:4326" }
           }
        }
     }
  }
}

The custom MongoDB CRS uses a counter-clockwise winding order and allows $geoIntersects to support queries with a single-ringed GeoJSON polygon whose area is greater than or equal to a single hemisphere. If the specified polygon is smaller than a single hemisphere, the behavior of $geoIntersects with the MongoDB CRS is the same as with the default CRS. See also “Big” Polygons.

Important

If you use longitude and latitude, specify coordinates in order of: longitude, latitude.

Behavior¶

Geospatial Indexes¶

$geoIntersects uses spherical geometry. $geoIntersects does not require a geospatial index. However, a geospatial index will improve query performance. Only the 2dsphere geospatial index supports $geoIntersects.

“Big” Polygons¶

For $geoIntersects, if you specify a single-ringed polygon that has an area greater than a single hemisphere, include the custom MongoDB coordinate reference system in the $geometry expression; otherwise, $geoIntersects queries for the complementary geometry. For all other GeoJSON polygons with areas greater than a hemisphere, $geoIntersects queries for the complementary geometry.

Examples¶

Intersects a Polygon¶

The following example uses $geoIntersects to select all loc data that intersect with the Polygon defined by the coordinates array. The area of the polygon is less than the area of a single hemisphere:

db.places.find(
   {
     loc: {
       $geoIntersects: {
          $geometry: {
             type: "Polygon" ,
             coordinates: [
               [ [ 0, 0 ], [ 3, 6 ], [ 6, 1 ], [ 0, 0 ] ]
             ]
          }
       }
     }
   }
)

For single-ringed polygons with areas greater than a single hemisphere, see Intersects a “Big” Polygon.

Intersects a “Big” Polygon¶

To query with a single-ringed GeoJSON polygon whose area is greater than a single hemisphere, the $geometry expression must specify the custom MongoDB coordinate reference system. For example:

db.places.find(
   {
     loc: {
       $geoIntersects: {
          $geometry: {
             type : "Polygon",
             coordinates: [
               [
                 [ -100, 60 ], [ -100, 0 ], [ -100, -60 ], [ 100, -60 ], [ 100, 60 ], [ -100, 60 ]
               ]
             ],
             crs: {
                type: "name",
                properties: { name: "urn:x-mongodb:crs:strictwinding:EPSG:4326" }
             }
          }
       }
     }
   }
)

← $geoWithin $near →

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