/*
* 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 java.util.Date;
import org.opengis.referencing.IdentifiedObject;
import org.opengis.metadata.extent.Extent;
import org.opengis.util.InternationalString;
import org.opengis.annotation.UML;
import static org.opengis.annotation.Obligation.*;
import static org.opengis.annotation.Specification.*;
/**
* Specifies the relationship of a coordinate system to the earth, thus creating a {@linkplain
* org.opengis.referencing.crs.CoordinateReferenceSystem coordinate reference system}. A datum uses a
* parameter or set of parameters that determine the location of the origin of the coordinate
* reference system. Each datum subtype can be associated with only specific types of
* {@linkplain org.opengis.referencing.cs.CoordinateSystem coordinate systems}.
*
*
* @source $URL: http://svn.osgeo.org/geotools/branches/2.7.x/modules/library/opengis/src/main/java/org/opengis/referencing/datum/Datum.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
*
* @see org.opengis.referencing.cs.CoordinateSystem
* @see org.opengis.referencing.crs.CoordinateReferenceSystem
*/
@UML(identifier="CD_Datum", specification=ISO_19111)
public interface Datum extends IdentifiedObject {
/**
* Key for the <code>{@value}</code> property to be given to the
* {@linkplain DatumFactory datum factory} <code>createFoo(…)</code> methods.
* This is used for setting the value to be returned by {@link #getAnchorPoint}.
*
* @see #getAnchorPoint
*/
String ANCHOR_POINT_KEY = "anchorPoint";
/**
* Key for the <code>{@value}</code> property to be given to the
* {@linkplain DatumFactory datum factory} <code>createFoo(…)</code> methods.
* This is used for setting the value to be returned by {@link #getRealizationEpoch}.
*
* @see #getRealizationEpoch
*/
String REALIZATION_EPOCH_KEY = "realizationEpoch";
/**
* Key for the <code>{@value}</code> property to be given to the
* {@linkplain DatumFactory datum factory} <code>createFoo(…)</code> methods.
* This is used for setting the value to be returned by {@link #getDomainOfValidity}.
*
* @see #getDomainOfValidity
*
* @since GeoAPI 2.1
*/
String DOMAIN_OF_VALIDITY_KEY = "domainOfValidity";
/**
* Key for the <code>{@value}</code> property to be given to the
* {@linkplain DatumFactory datum factory} <code>createFoo(…)</code> methods.
* This is used for setting the value to be returned by {@link #getScope}.
*
* @see #getScope
*/
String SCOPE_KEY = "scope";
/**
* Description, possibly including coordinates, of the point or points used to anchor the datum
* to the Earth. Also known as the "origin", especially for Engineering and Image Datums.
* <p>
* <ul>
* <li>For a geodetic datum, this point is also known as the fundamental point, which is
* traditionally the point where the relationship between geoid and ellipsoid is defined.
* In some cases, the "fundamental point" may consist of a number of points. In those
* cases, the parameters defining the geoid/ellipsoid relationship have then been averaged
* for these points, and the averages adopted as the datum definition.</li>
*
* <li>For an engineering datum, the anchor point may be a physical point, or it may be a
* point with defined coordinates in another CRS.</li>
*
* <li>For an image datum, the anchor point is usually either the centre of the image or the
* corner of the image.</li>
*
* <li>For a temporal datum, this attribute is not defined. Instead of the anchor point,
* a temporal datum carries a separate time origin of type {@link Date}.</li>
* </ul>
*
* @return A description of the anchor point, or {@code null} if none.
*/
@UML(identifier="anchorPoint", obligation=OPTIONAL, specification=ISO_19111)
InternationalString getAnchorPoint();
/**
* The time after which this datum definition is valid. This time may be precise (e.g. 1997
* for IRTF97) or merely a year (e.g. 1983 for NAD83). In the latter case, the epoch usually
* refers to the year in which a major recalculation of the geodetic control network, underlying
* the datum, was executed or initiated. An old datum can remain valid after a new datum is
* defined. Alternatively, a datum may be superseded by a later datum, in which case the
* realization epoch for the new datum defines the upper limit for the validity of the
* superseded datum.
*
* @return The datum realization epoch, or {@code null} if not available.
*/
@UML(identifier="realizationEpoch", obligation=OPTIONAL, specification=ISO_19111)
Date getRealizationEpoch();
/**
* Area or region or timeframe in which this datum is valid.
*
* @return The datum valid domain, or {@code null} if not available.
*
* @since GeoAPI 2.1
*/
@UML(identifier="domainOfValidity", obligation=OPTIONAL, specification=ISO_19111)
Extent getDomainOfValidity();
/**
* Description of domain of usage, or limitations of usage, for which this
* datum object is valid.
*
* @return A description of domain of usage, or {@code null} if none.
*/
@UML(identifier="scope", obligation=OPTIONAL, specification=ISO_19111)
InternationalString getScope();
}