Parameter
---------

Next up we have a quick API for representing parameters coming out of the
OGC Abstraction specification.

Much like with with Record and RecordType we have a split between ParameterValue and ParameterDescriptor.

Here is what ParameterValue looks like:

.. image:: /images/parameter_value.PNG

And the associated descriptors:

.. image:: /images/parameter_descriptor.PNG

We have a default implementation in **gt-referencing** which we can use for a code example of both pieces working together::

  final DefaultParameterDescriptor RANGE =
      new DefaultParameterDescriptor("Range", 15.0, -30.0, +40.0, null)

  ParameterValue value = (ParameterValue) RANGE.createValue();
  value.setValue( 2.0 );   

Parameters are used in a few sections of the library, notably when working with imagery and referencing.