MongoDB Shape-Based Search

This chapter introduces MongoDB's geospatial query, which supports geometric intersection and containment queries.

Application scenarios:

• Draw a circle on the map and query the data within the circle.

Prerequisite Tutorial

Geospatial Data Storage Formats for MongoDB

The prerequisites for querying data based on distance are as follows:

• Each document data contains a field for storing coordinate data, for example: the location field stores the coordinates of a store.
• Create a 2dsphere or 2d spatial index.

$geoWithin Operator

It is commonly used to query coordinate points contained within a specified geometric range, for example: when searching for houses by drawing on a map, draw an area on the map and query the houses within that area.

Syntax format:

{
   <location field>: { // Query field
      $geoWithin: {
         $geometry: {
            type:  , // Only supports Polygon or MultiPolygon.
            coordinates: [ <coordinates> ]  // Collection of geometric coordinate points
         }
      }
   }
}

Example:

db.places.find(
   {
     loc: { // The loc field stores the coordinate data
       $geoWithin: {
          $geometry: {
             type: "Polygon" ,
             coordinates: [ [ [ 0, 0 ], [ 3, 6 ], [ 6, 1 ], [ 0, 0 ] ] ] // Find data within this geometric area
          }
       }
     }
   }
)

Query for document data within the specified geometric area in the places collection.

$geoIntersects Operator

The difference from $geoWithin is that $geoIntersects is used to determine whether there is an intersection between two geometries.

Format:

{
  <location field>: { // Field storing geometric coordinate points
     $geoIntersects: {
        $geometry: {
           type: "<geojson object type>" , // Geometric type
           coordinates: [ <coordinates> ] // Collection of geometric coordinate points, query data with intersection with this geometry
        }
     }
  }
}

Example:

db.places.find(
   {
     loc: { // The loc field stores area data, which is a geometric shape
       $geoIntersects: {
          $geometry: {
             type: "Polygon" ,
             coordinates: [
               [ [ 0, 0 ], [ 3, 6 ], [ 6, 1 ], [ 0, 0 ] ] // Query data with intersection with this geometry
             ]
          }
       }
     }
   }
)