Search Geospatially

GeoJSON Positions

A position represents a single place on Earth, and exists in code as an array containing two or three number values:

• Longitude in the first position (required)

• Latitude in the second position (required)

• Elevation in the third position (optional)

GeoJSON Types

Your GeoJSON object's type determines its geometric shape. Geometric shapes are made up of positions.

Here are some common GeoJSON types and how you can specify them with positions:

• Point: a single position. This could represent the location of a sculpture.

• LineString: an array of two or more positions, thus forming a series of line segments. This could represent the route of the Great Wall of China.

• Polygon: an array of positions in which the first and last position are the same, thus enclosing some space. This could represent the land within Vatican City.

To learn more about the shapes you can use in MongoDB, see the GeoJSON manual entry.

Index

To query data stored in the GeoJSON format, add the field containing GeoJSON data to a 2dsphere index. The following snippet creates a 2dsphere index on the location.geo field using the Indexes builder:

// <MongoCollection setup code here>
collection.createIndex(Indexes.geo2dsphere("location.geo"));

For more information on the Indexes builder, see our guide on the Indexes builder.

Index

To query data stored as legacy coordinate pairs, you must add the field containing legacy coordinate pairs to a 2d index. The following snippet creates a 2d index on the coordinates field using the Indexes builder:

// <MongoCollection setup code here>
collection.createIndex(Indexes.geo2d("coordinates"));

For more information on the Indexes builder, see our guide on the Indexes builder.

For more information on legacy coordinate pairs, see the MongoDB Server manual page on legacy coordinate pairs.

Query Operators

To query your geospatial data, use one of the following query operators:

• $near

• $geoWithin

• $nearSphere

• $geoIntersects requires a 2dsphere index

You can specify these query operators in the MongoDB Java driver with the near(), geoWithin(), nearSphere(), and geoIntersects() utility methods of the Filters builder class.

For more information on geospatial query operators, see the manual entry for geospatial queries.

For more information on Filters, see our guide on the Filters builder.

Query Parameters

To specify a shape to use in a geospatial query, use the Position, Point, LineString, and Polygon classes of the MongoDB Java driver.

For a full list of the GeoJSON shapes available in the MongoDB Java driver, see the GeoJSON package API Documentation.

Query by Proximity

To search for and return documents from nearest to farthest from a point, use the near() static utility method of the Filters builder class. The near() method constructs a query with the $near query operator.

The following example queries for theaters between 10,000 and 5,000 meters from the Great Lawn of Central Park.

// code to set up your mongo client ...
MongoDatabase database = mongoClient.getDatabase("sample_mflix");
MongoCollection<Document> collection = database.getCollection("theaters");
Point centralPark = new Point(new Position(-73.9667, 40.78));
Bson query = near("location.geo", centralPark, 10000.0, 5000.0);
Bson projection = fields(include("location.address.city"), excludeId());
collection.find(query)
        .projection(projection)
        .forEach(doc -> System.out.println(doc.toJson()));

The output of the code snippet should look something like this:

{"location": {"address": {"city": "Bronx"}}}
{"location": {"address": {"city": "New York"}}}
{"location": {"address": {"city": "New York"}}}
{"location": {"address": {"city": "Long Island City"}}}
{"location": {"address": {"city": "New York"}}}
{"location": {"address": {"city": "Secaucus"}}}
{"location": {"address": {"city": "Jersey City"}}}
{"location": {"address": {"city": "Elmhurst"}}}
{"location": {"address": {"city": "Flushing"}}}
{"location": {"address": {"city": "Flushing"}}}
{"location": {"address": {"city": "Flushing"}}}
{"location": {"address": {"city": "Elmhurst"}}}

For more information on the $near operator, see the reference documentation for $near.

For more information on Filters, see our guide on the Filters builder.

Query Within a Range

To search for geospatial data within a specified shape use the geoWithin() static utility method of the Filters builder class. The geoWithin() method constructs a query with the $geoWithin query operator.

The following example searches for movie theaters in a section of Long Island.

// code to set up your mongo collection ...
Polygon longIslandTriangle = new Polygon(Arrays.asList(new Position(-72, 40),
        new Position(-74, 41),
        new Position(-72, 39),
        new Position(-72, 40)));
Bson projection = fields(include("location.address.city"), excludeId());
Bson geoWithinComparison = geoWithin("location.geo", longIslandTriangle);
collection.find(geoWithinComparison)
        .projection(projection)
        .forEach(doc -> System.out.println(doc.toJson()));

The output of the code snippet should look something like this:

{"location": {"address": {"city": "Baldwin"}}}
{"location": {"address": {"city": "Levittown"}}}
{"location": {"address": {"city": "Westbury"}}}
{"location": {"address": {"city": "Mount Vernon"}}}
{"location": {"address": {"city": "Massapequa"}}}

The following figure shows the polygon defined by the longIslandTriangle variable and dots representing the locations of the movie theaters returned by our query.

For more information on the $geoWithin operator, see the reference documentation for $geoWithin

For more information on the operators you can use in your query, see the MongoDB Server manual page on geospatial query operators