.. include-document:: org.gvsig.fmap.geom/reference-links
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All the geometries that you want to use in the application must have a type (GeometryType_) previously registered. If we try to create a geometry with a non-registered type in the GeometryManager_, we will get an exception of the kind CreateGeometryException_.

To register a new geometry type, first of all we must obtain an instance of the GeometryManager_ and, later, we will register the implementation of the geometry type. To do this, we must know the geometry type and subtype. The diferent kinds of types are defined on TYPES_, and the subtypes in SUBTYPES_.

In the next example we show how to register a 2-dimensional point (is assumed that exists a Point2D class which inherits from Geometry_).

.. code-block:: java

  geometryManager.registerGeometryType(Point2D.class, "Point2D", TYPES.POINT, SUBTYPES.GEOM2D);

The method *registerGeometryType* has 4 parameters. First of them is the class which contains the geometry implementation; the second one is the name to register and, the third and fourth, the geometry type and subtype.

In this case, is registering the default geometry for the type 2-dimensional point. When we invoke this method, the manager will associate to the specified type and subtype the implementation of the geometry that we have passed in first parameter, so that, when we create a geometry with that types, the manager will return an instance of the Point2D class.

The next example shows how to register a 3-dimensional point. The example assums that exists a Point3D class which inherits from Geometry_ and implements a 3-dimensional point:

.. code-block:: java

  geometryManager.registerGeometryType(Point3D.class, "Point3D", TYPES.POINT, SUBTYPES.GEOM3D);

In this other example, we register a geometry of the circle type. The example assums that exists a Circle2D class which inherits from Geometry_ and implements a 2-dimensional circle:

.. code-block:: java

  geometryManager.registerGeometryType (Circle2D.class, "Circle2D", TYPES.CIRCLE, SUBTYPES.GEOM2D);