OPTIONS

geoNear

Definition

geoNear

Returns documents in order of proximity to a specified point, from the nearest to farthest. geoNear requires a geospatial index.

The geoNear command accepts a document that contains the following fields. Specify all distances in the same units as the document coordinate system:

Field Description
geoNear The collection to query.
near

The point for which to find the closest documents.

If using a 2dsphere index, you can specify the point as either a GeoJSON point or legacy coordinate pair.

If using a 2d index, specify the point as a legacy coordinate pair.

spherical

Required if using a 2dsphere index. Determines how MongoDB calculates the distance. The default value is false.

If true, then MongoDB uses spherical geometry to calculate distances in meters if the specified (near) point is a GeoJSON point and in radians if the specified (near) point is a legacy coordinate pair.

If false, then MongoDB uses 2d planar geometry to calculate distance between points.

If using a 2dsphere index, spherical must be true.

limit Optional. The maximum number of documents to return. The default value is 100. See also the num option.
num Optional. The num option provides the same function as the limit option. Both define the maximum number of documents to return. If both options are included, the num value overrides the limit value.
minDistance

Optional. The minimum distance from the center point that the documents must be. MongoDB filters the results to those documents that are at least the specified distance from the center point.

Only available for use with 2dsphere index.

Specify the distance in meters for GeoJSON data and in radians for legacy coordinate pairs.

New in version 2.6.

maxDistance

Optional. The maximum distance from the center point that the documents can be. MongoDB limits the results to those documents that fall within the specified distance from the center point.

Specify the distance in meters for GeoJSON data and in radians for legacy coordinate pairs.

query

Optional. Limits the results to the documents that match the query. The query syntax is the usual MongoDB read operation query syntax.

You cannot specify a $near predicate in the query field of the geoNear command.

distanceMultiplier Optional. The factor to multiply all distances returned by the query. For example, use the distanceMultiplier to convert radians, as returned by a spherical query, to kilometers by multiplying by the radius of the Earth.
includeLocs Optional. If this is true, the query returns the location of the matching documents in the results. The default is false. This option is useful when a location field contains multiple locations. To specify a field within an embedded document, use dot notation.
uniqueDocs

Optional. If this value is true, the query returns a matching document once, even if more than one of the document’s location fields match the query.

Deprecated since version 2.6: Geospatial queries no longer return duplicate results. The $uniqueDocs operator has no impact on results.

Considerations

geoNear requires a geospatial index. However, the geoNear command requires that a collection have at most only one 2d index and/or only one 2dsphere.

Queries that use a 2d index return a limit of 100 documents.

You cannot specify a $near predicate in the query field of the geoNear command.

Command Syntax

2dsphere Index

If using a 2dsphere index, you can specify either a GeoJSON point or a legacy coordinate pair for the near value.

You must include spherical: true in the syntax.

With spherical: true, if you specify a GeoJSON point, MongoDB uses meters as the unit of measurement:

db.runCommand( {
   geoNear: <collection> ,
   near: { type: "Point" , coordinates: [ <coordinates> ] } ,
   spherical: true,
   ...
} )

With spherical: true, if you specify a legacy coordinate pair, MongoDB uses radians as the unit of measurement:

db.runCommand( {
   geoNear: <collection> ,
   near: [ <coordinates> ],
   spherical: true,
   ...
} )

2d Index

To query a 2d index, use the following syntax:

db.runCommand( {
   geoNear: <collection>,
   near : [ <coordinates> ],
   ...
} )

If you specify spherical: true, MongoDB uses spherical geometry to calculate distances in radians. Otherwise, MongoDB uses planar geometry to calculate distances between points.

Behavior

geoNear always returns the documents sorted by distance. Any other sort order requires to sort the documents in memory, which can be inefficient. To return results in a different sort order, use the $geoWithin operator and the sort() method.

Because geoNear orders the documents from nearest to farthest, the minDistance field effectively skips over the first n documents where n is determined by the distance requirement.

The geoNear command provides an alternative to the $near operator. In addition to the functionality of $near, geoNear returns additional diagnostic information.

Examples

The following examples run the geoNear command on the collection places that has a 2dsphere index.

Specify a Query Condition

The following geoNear command queries for documents whose category equals "public" and returns the matching documents in order of nearest to farthest to the specified point:

db.runCommand(
   {
     geoNear: "places",
     near: { type: "Point", coordinates: [ -73.9667, 40.78 ] },
     spherical: true,
     query: { category: "public" }
   }
)

The operation returns the following output, the documents in the results from nearest to farthest:

{
  "results" : [
     {
       "dis" : 0,
       "obj" : {
          "_id" : 2,
          "location" : { "type" : "Point", "coordinates" : [ -73.9667, 40.78 ] },
          "name" : "Central Park",
          "category" : "public"
       }
     },
     {
       "dis" : 3245.988787957091,
       "obj" : {
          "_id" : 3,
          "location" : { "type" : "Point", "coordinates" : [ -73.9836, 40.7538 ] },
          "name" : "Bryant Park",
          "category" : "public"
       }
     },
     {
       "dis" : 7106.506152782733,
       "obj" : {
          "_id" : 4,
          "location" : { "type" : "Point", "coordinates" : [ -73.9928, 40.7193 ] },
          "name" : "Sara D. Roosevelt Park",
          "category" : "public"
       }
     },

  ],
  "stats" : {
     "nscanned" : NumberLong(47),
     "objectsLoaded" : NumberLong(47),
     "avgDistance" : 3450.8316469132747,
     "maxDistance" : 7106.506152782733,
     "time" : 4
  },
  "ok" : 1
}

Specify a minDistance and maxDistance

The following example specifies a minDistance of 3000 meters and maxDistance of 7000 meters:

db.runCommand(
   {
     geoNear: "places",
     near: { type: "Point", coordinates: [ -73.9667, 40.78 ] },
     spherical: true,
     query: { category: "public" },
     minDistance: 3000,
     maxDistance: 7000
   }
)

The operation returns the following output:

{
  "results" : [
     {
       "dis" : 3245.988787957091,
       "obj" : {
          "_id" : 3,
          "location" : { "type" : "Point", "coordinates" : [ -73.9836, 40.7538 ] },
          "name" : "Bryant Park",
          "category" : "public"
       }
     }
  ],
  "stats" : {
      "nscanned" : NumberLong(11),
      "objectsLoaded" : NumberLong(11),
      "avgDistance" : 3245.988787957091,
      "maxDistance" : 3245.988787957091,
      "time" : 0
  },
  "ok" : 1
}

Output

The geoNear command returns a document with the following fields:

geoNear.results

An array with the results of the geoNear command, sorted by distance with the nearest result listed first and farthest last.

geoNear.results[n].dis

For each document in the results, the distance from the coordinates defined in the geoNear command.

geoNear.results[n].obj

The document from the collection.

geoNear.stats

An object with statistics about the query used to return the results of the geoNear search.

geoNear.stats.nscanned

The total number of index entries scanned during the database operation.

geoNear.stats.objectsLoaded

The total number of documents read from disk during the database operation.

geoNear.stats.avgDistance

The average distance between the coordinates defined in the geoNear command and coordinates of the documents returned as results.

geoNear.stats.maxDistance

The maximum distance between the coordinates defined in the geoNear command and coordinates of the documents returned as results.

geoNear.stats.time

The execution time of the database operation, in milliseconds.

geoNear.ok

A value of 1 indicates the geoNear search succeeded. A value of 0 indicates an error.