/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2011, Open Source Geospatial Foundation (OSGeo)
 *    (C) 2003-2005, Open Geospatial Consortium Inc.
 *    
 *    All Rights Reserved. http://www.opengis.org/legal/
 */
package org.opengis.referencing.datum;

import org.opengis.annotation.UML;

import static org.opengis.annotation.Obligation.*;
import static org.opengis.annotation.Specification.*;


/**
 * A textual description and/or a set of parameters identifying a particular reference level
 * surface used as a zero-height surface. The description includes its position with respect
 * to the Earth for any of the height types recognized by this standard. There are several
 * types of Vertical Datums, and each may place constraints on the
 * {@linkplain org.opengis.referencing.cs.CoordinateSystemAxis Coordinate Axis} with which
 * it is combined to create a {@linkplain org.opengis.referencing.crs.VerticalCRS Vertical CRS}.
 *
 *
 * @source $URL: http://svn.osgeo.org/geotools/branches/2.7.x/modules/library/opengis/src/main/java/org/opengis/referencing/datum/VerticalDatum.java $
 * @version <A HREF="http://portal.opengeospatial.org/files/?artifact_id=6716">Abstract specification 2.0</A>
 * @author  Martin Desruisseaux (IRD)
 * @since   GeoAPI 1.0
 */
@UML(identifier="CD_VerticalDatum", specification=ISO_19111)
public interface VerticalDatum extends Datum {
    /**
     * The type of this vertical datum. Default is "geoidal".
     *
     * @return The type of this vertical datum.
     */
    @UML(identifier="vertDatumType", obligation=MANDATORY, specification=ISO_19111)
    VerticalDatumType getVerticalDatumType();
}
