001/*
002 *    GeoAPI - Java interfaces for OGC/ISO standards
003 *    Copyright © 2006-2023 Open Geospatial Consortium, Inc.
004 *    http://www.geoapi.org
005 *
006 *    Licensed under the Apache License, Version 2.0 (the "License");
007 *    you may not use this file except in compliance with the License.
008 *    You may obtain a copy of the License at
009 *
010 *        http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *    Unless required by applicable law or agreed to in writing, software
013 *    distributed under the License is distributed on an "AS IS" BASIS,
014 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 *    See the License for the specific language governing permissions and
016 *    limitations under the License.
017 */
018package org.opengis.referencing.crs;
019
020import org.opengis.referencing.datum.DatumEnsemble;
021import org.opengis.referencing.datum.GeodeticDatum;
022import org.opengis.annotation.UML;
023
024import static org.opengis.annotation.Obligation.*;
025import static org.opengis.annotation.Specification.*;
026
027
028/**
029 * A 2- or 3-dimensional <abbr>CRS</abbr> used over the whole planet or substantial parts of it.
030 * This is used to describe large portions of the planet's surface up to the entire planet's surface.
031 * If the geodetic reference frame is dynamic then the geodetic <abbr>CRS</abbr> is dynamic, else it is static.
032 *
033 * <h2>Permitted coordinate systems</h2>
034 * This type of <abbr>CRS</abbr> can be used with coordinate systems of type
035 * {@link org.opengis.referencing.cs.CartesianCS},
036 * {@link org.opengis.referencing.cs.SphericalCS} or
037 * {@link org.opengis.referencing.cs.EllipsoidalCS}.
038 * In the latter case, the {@link GeographicCRS} specialization should be used.
039 *
040 * @author  OGC Topic 2 (for abstract model and documentation)
041 * @author  Martin Desruisseaux (IRD, Geomatys)
042 * @version 3.1
043 * @since   2.1
044 */
045@UML(identifier="GeodeticCRS", specification=ISO_19111)
046public interface GeodeticCRS extends SingleCRS {
047    /**
048     * Returns the reference frame, which shall be geodetic.
049     * This property may be null if this <abbr>CRS</abbr> is related to an object
050     * identified only by a {@linkplain #getDatumEnsemble() datum ensemble}.
051     *
052     * @return the reference frame, or {@code null} if this <abbr>CRS</abbr> is related to
053     *         an object identified only by a {@linkplain #getDatumEnsemble() datum ensemble}.
054     *
055     * @condition Mandatory if the {@linkplain #getDatumEnsemble() datum ensemble} is not documented.
056     */
057    @Override
058    @UML(identifier="datum", obligation=CONDITIONAL, specification=ISO_19111)
059    GeodeticDatum getDatum();
060
061    /**
062     * Returns the datum ensemble, whose members shall be geodetic reference frames.
063     * This property may be null if this <abbr>CRS</abbr> is related to an object
064     * identified only by a single {@linkplain #getDatum() datum}.
065     *
066     * <p>The default implementation returns {@code null}.</p>
067     *
068     * @return the datum ensemble, or {@code null} if this <abbr>CRS</abbr> is related
069     *         to an object identified only by a single {@linkplain #getDatum() datum}.
070     *
071     * @condition Mandatory if the {@linkplain #getDatum() datum} is not documented.
072     * @since 3.1
073     */
074    @Override
075    @UML(identifier="datumEnsemble", obligation=CONDITIONAL, specification=ISO_19111)
076    default DatumEnsemble<GeodeticDatum> getDatumEnsemble() {
077        return null;
078    }
079}