Geospatial Search

You can query against geospatial indexes in several ways via the Node.js driver, using geospatial query operators.

To create a 2dsphere index on a collection, pass a document containing the name of the field to be indexed with the value ‘2dsphere’ to the createIndex() method.

var create2dSphereIndex = function(db, callback) {
  // Get the restaurants collection
  var collection = db.collection('restaurants');
  // Create the index
  collection.createIndex(
    { 'address.coord' : "2dsphere" }, function(err, result) {
    console.log(result);
    callback(result);
  });
};

// use the create2dSphereIndex function
var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');

// Connection URL
var url = 'mongodb://localhost:27017/test';
// Use connect method to connect to the server
MongoClient.connect(url, function(err, db) {
  assert.equal(null, err);
  console.log("Connected correctly to server");
  create2dSphereIndex(db, function() {
    db.close();
  });
});

The following examples assume that a database called test has a collection called restaurants, with a 2d sphere index index on the address.coord field. A sample dataset is available for download.

$near

The $near operator specifies a set of longitude-latitude coordinates and returns documents from nearest to farthest.

var findDocuments = function(db, callback) {
  // Get the documents collection
  var collection = db.collection('restaurants');
  // Find some documents
  collection.find(
	{ 'address.coord':
	  { $near :
	    { $geometry:
	      { type: "Point",  coordinates: [ -73.9667, 40.78 ] },
	        $maxDistance: 1000
	    }
	  }
	}
  ).toArray(function(err, docs) {
    assert.equal(err, null);
    console.log("Found the following records");
    console.log(docs);
    callback(docs);
  });      
}

// use the findDocuments() function
var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');

// Connection URL
var url = 'mongodb://localhost:27017/test';
// Use connect method to connect to the server
MongoClient.connect(url, function(err, db) {
  assert.equal(null, err);
  console.log("Connected correctly to server");
  findDocuments(db, function() {
    db.close();
  });
});

The $maxDistance option specifies a maximum distance (in meters) from the given coordinates. For a complete list of $near options, see the MongoDB manual.

$geoWithin

The $geoWithin operator selects documents with geospatial data that exist within a specified shape.

var findDocuments = function(db, callback) {
  // Get the documents collection
  var collection = db.collection('restaurants');
  // Find some documents
  collection.find(
    { 'address.coord':
      { $geoWithin:
 	   { $geometry:
 	     { type : "Polygon" ,
            coordinates: [ [ [ -73, 40 ], [ -74, 41 ], [ -72, 39 ], [ -73, 40 ] ] ]
          }
        }
      }
    }
  ).toArray(function(err, docs) {
    assert.equal(err, null);
    console.log("Found the following records");
    console.log(docs);
    callback(docs);
  });      
}

// use the findDocuments() function
var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');

// Connection URL
var url = 'mongodb://localhost:27017/test';
// Use connect method to connect to the server
MongoClient.connect(url, function(err, db) {
  assert.equal(null, err);
  console.log("Connected correctly to server");
  findDocuments(db, function() {
    db.close();
  });
});