How to Query All Objects within an n Kilometer Radius Using Hibernate Spatial

How can I effectively query all objects within an n kilometer radius in Hibernate Spatial?

import org.hibernate.spatial.GeometryType;
import org.hibernate.query.Query;
import org.locationtech.jts.geom.Point;

// Assuming session is a valid Hibernate Session
// and MyEntity is the entity to query
// latitude and longitude define the center point
Point centerPoint = geometryFactory.createPoint(new Coordinate(longitude, latitude));

String hql = "FROM MyEntity e WHERE ST_DWithin(e.location, :center, :radius)";
Query<MyEntity> query = session.createQuery(hql, MyEntity.class);
query.setParameter("center", centerPoint);
query.setParameter("radius", radiusInMeters);
List<MyEntity> results = query.getResultList();

Hibernate Spatial provides powerful capabilities for handling geospatial data within Hibernate-based applications. This answer outlines how to effectively query for all entities within a specified radius using spatial functions available in the library.

import org.hibernate.spatial.GeometryType;
import org.hibernate.query.Query;
import org.locationtech.jts.geom.Point;

// Assuming session is a valid Hibernate Session
// and MyEntity is the entity to query
// latitude and longitude define the center point
Point centerPoint = geometryFactory.createPoint(new Coordinate(longitude, latitude));

String hql = "FROM MyEntity e WHERE ST_DWithin(e.location, :center, :radius)";
Query<MyEntity> query = session.createQuery(hql, MyEntity.class);
query.setParameter("center", centerPoint);
query.setParameter("radius", radiusInMeters);
List<MyEntity> results = query.getResultList();

Causes

• Improper setup of Hibernate Spatial configurations.
• Incorrect use of spatial types or functions.
• Not using the correct spatial database provider.

Solutions

• Ensure that Hibernate Spatial is correctly configured in your project.
• Use the appropriate geometrical functions like ST_DWithin() to filter results by distance.
• Make sure your database contains spatial data types (e.g., PostGIS for PostgreSQL).

Mistake: Using latitude and longitude in the wrong format.

Solution: Ensure you create the Point object using the correct coordinate format: (longitude, latitude).

Mistake: Not specifying the radius in meters while querying.

Solution: Always convert your radius from kilometers to meters before passing to the query.

Mistake: Not initializing the geometryFactory correctly for Point creation.

Solution: Instantiate the GeometryFactory based on the coordinate reference system you are using.