Geospatial Search

Prerequisites

You must set up the following components to run the code examples in this guide:

• A test.restaurants collection populated with documents from the restaurants.json file in the documentation assets GitHub.

• The following import statements:

import com.mongodb.reactivestreams.client.MongoClients;
import com.mongodb.reactivestreams.client.MongoClient;
import com.mongodb.reactivestreams.client.MongoCollection;
import com.mongodb.reactivestreams.client.MongoDatabase;
import com.mongodb.client.model.geojson.*;
import com.mongodb.client.model.Indexes;
import com.mongodb.client.model.Filters;
import org.bson.Document;

Connect to a MongoDB Deployment

First, connect to a MongoDB deployment, then declare and define MongoDatabase and MongoCollection instances.

The following code connects to a standalone MongoDB deployment running on localhost on port 27017. Then, it defines the database variable to refer to the test database and the collection variable to refer to the restaurants collection:

MongoClient mongoClient = MongoClients.create();
MongoDatabase database = mongoClient.getDatabase("test");
MongoCollection<Document> collection = database.getCollection("restaurants");

To learn more about connecting to MongoDB deployments, see the Connect to MongoDB tutorial.

Create the 2dsphere Index

To create a 2dsphere index, use the Indexes.geo2dsphere() helper to create a specification for the 2dsphere index. Pass the specification to the MongoCollection.createIndex() method to create the index.

The following example creates a 2dsphere index on the "contact.location" field in the restaurants collection:

MongoCollection<Document> collection = database.getCollection("restaurants");
collection.createIndex(Indexes.geo2dsphere("contact.location"))
    .subscribe(new PrintSubscriber<String>());

Query for Locations Near a GeoJSON Point

MongoDB provides various geospatial query operators. To facilitate the creation of geospatial query filters, the driver provides the Filters class and the com.mongodb.client.model.geojson package.

The following example returns documents that are at least 1000 meters and at most 5000 meters from the specified GeoJSON Point instance, sorted from nearest to farthest:

Point refPoint = new Point(new Position(-73.9667, 40.78));
collection.find(Filters.near("contact.location", refPoint, 5000.0, 1000.0))
    .subscribe(new PrintDocumentSubscriber());