001: /*
002: * GeoTools - OpenSource mapping toolkit
003: * http://geotools.org
004: * (C) 2003-2006, GeoTools Project Managment Committee (PMC)
005: * (C) 2001, Institut de Recherche pour le Développement
006: *
007: * This library is free software; you can redistribute it and/or
008: * modify it under the terms of the GNU Lesser General Public
009: * License as published by the Free Software Foundation;
010: * version 2.1 of the License.
011: *
012: * This library is distributed in the hope that it will be useful,
013: * but WITHOUT ANY WARRANTY; without even the implied warranty of
014: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015: * Lesser General Public License for more details.
016: *
017: * This package contains documentation from OpenGIS specifications.
018: * OpenGIS consortium's work is fully acknowledged here.
019: */
020: package org.geotools.referencing.datum;
021:
022: // J2SE dependencies
023: import java.util.Date;
024: import java.util.HashMap;
025: import java.util.Map;
026:
027: // OpenGIS dependencies
028: import org.opengis.metadata.extent.Extent;
029: import org.opengis.referencing.datum.Datum;
030: import org.opengis.util.InternationalString;
031:
032: // Geotools dependencies
033: import org.geotools.referencing.AbstractIdentifiedObject;
034: import org.geotools.referencing.wkt.Formatter;
035: import org.geotools.resources.Utilities;
036:
037: /**
038: * Specifies the relationship of a coordinate system to the earth, thus creating a {@linkplain
039: * org.opengis.referencing.crs.CoordinateReferenceSystem coordinate reference system}. A datum
040: * uses a parameter or set of parameters that determine the location of the origin of the coordinate
041: * reference system. Each datum subtype can be associated with only specific types of
042: * {@linkplain org.opengis.referencing.cs.AbstractCS coordinate systems}.
043: * <p>
044: * A datum can be defined as a set of real points on the earth that have coordinates.
045: * The definition of the datum may also include the temporal behavior (such as the
046: * rate of change of the orientation of the coordinate axes).
047: * <p>
048: * This class is conceptually <cite>abstract</cite>, even if it is technically possible to
049: * instantiate it. Typical applications should create instances of the most specific subclass with
050: * {@code Default} prefix instead. An exception to this rule may occurs when it is not possible to
051: * identify the exact type.
052: *
053: * @source $URL: http://svn.geotools.org/geotools/tags/2.4.1/modules/library/referencing/src/main/java/org/geotools/referencing/datum/AbstractDatum.java $
054: * @version $Id: AbstractDatum.java 28264 2007-12-05 21:53:08Z desruisseaux $
055: * @author Martin Desruisseaux
056: *
057: * @since 2.1
058: *
059: * @see org.geotools.referencing.cs.AbstractCS
060: * @see org.geotools.referencing.crs.AbstractCRS
061: */
062: public class AbstractDatum extends AbstractIdentifiedObject implements
063: Datum {
064: /**
065: * Serial number for interoperability with different versions.
066: */
067: private static final long serialVersionUID = -4894180465652474930L;
068:
069: /**
070: * List of localizable properties. To be given to
071: * {@link AbstractIdentifiedObject} constructor.
072: */
073: private static final String[] LOCALIZABLES = { ANCHOR_POINT_KEY,
074: SCOPE_KEY };
075:
076: /**
077: * Description, possibly including coordinates, of the point or points used to anchor the datum
078: * to the Earth. Also known as the "origin", especially for Engineering and Image Datums.
079: */
080: private final InternationalString anchorPoint;
081:
082: /**
083: * The time after which this datum definition is valid. This time may be precise
084: * (e.g. 1997 for IRTF97) or merely a year (e.g. 1983 for NAD83). If the time is
085: * not defined, then the value is {@link Long#MIN_VALUE}.
086: */
087: private final long realizationEpoch;
088:
089: /**
090: * Area or region in which this datum object is valid.
091: */
092: private final Extent domainOfValidity;
093:
094: /**
095: * Description of domain of usage, or limitations of usage, for which this
096: * datum object is valid.
097: */
098: private final InternationalString scope;
099:
100: /**
101: * Constructs a new datum with the same values than the specified one.
102: * This copy constructor provides a way to wrap an arbitrary implementation into a
103: * Geotools one or a user-defined one (as a subclass), usually in order to leverage
104: * some implementation-specific API. This constructor performs a shallow copy,
105: * i.e. the properties are not cloned.
106: *
107: * @since 2.2
108: */
109: public AbstractDatum(final Datum datum) {
110: super (datum);
111: final Date epoch = datum.getRealizationEpoch();
112: realizationEpoch = (epoch != null) ? epoch.getTime()
113: : Long.MIN_VALUE;
114: domainOfValidity = datum.getDomainOfValidity();
115: scope = datum.getScope();
116: anchorPoint = datum.getAnchorPoint();
117: }
118:
119: /**
120: * Constructs a datum from a set of properties. The properties given in argument follow
121: * the same rules than for the {@linkplain AbstractIdentifiedObject#AbstractIdentifiedObject(Map)
122: * super-class constructor}. Additionally, the following properties are understood by this
123: * construtor:
124: * <br><br>
125: * <table border='1'>
126: * <tr bgcolor="#CCCCFF" class="TableHeadingColor">
127: * <th nowrap>Property name</th>
128: * <th nowrap>Value type</th>
129: * <th nowrap>Value given to</th>
130: * </tr>
131: * <tr>
132: * <td nowrap> {@link #ANCHOR_POINT_KEY "anchorPoint"} </td>
133: * <td nowrap> {@link InternationalString} or {@link String} </td>
134: * <td nowrap> {@link #getAnchorPoint}</td>
135: * </tr>
136: * <tr>
137: * <td nowrap> {@link #REALIZATION_EPOCH_KEY "realizationEpoch"} </td>
138: * <td nowrap> {@link Date} </td>
139: * <td nowrap> {@link #getRealizationEpoch}</td>
140: * </tr>
141: * <tr>
142: * <td nowrap> {@link #DOMAIN_OF_VALIDITY_KEY "domainOfValidity"} </td>
143: * <td nowrap> {@link Extent} </td>
144: * <td nowrap> {@link #getDomainOfValidity}</td>
145: * </tr>
146: * <tr>
147: * <td nowrap> {@link #SCOPE_KEY "scope"} </td>
148: * <td nowrap> {@link InternationalString} or {@link String} </td>
149: * <td nowrap> {@link #getScope}</td>
150: * </tr>
151: * </table>
152: */
153: public AbstractDatum(final Map properties) {
154: this (properties, new HashMap());
155: }
156:
157: /**
158: * Work around for RFE #4093999 in Sun's bug database
159: * ("Relax constraint on placement of this()/super() call in constructors").
160: */
161: private AbstractDatum(final Map properties, final Map subProperties) {
162: super (properties, subProperties, LOCALIZABLES);
163: final Date realizationEpoch;
164: anchorPoint = (InternationalString) subProperties
165: .get(ANCHOR_POINT_KEY);
166: realizationEpoch = (Date) subProperties
167: .get(REALIZATION_EPOCH_KEY);
168: domainOfValidity = (Extent) subProperties
169: .get(DOMAIN_OF_VALIDITY_KEY);
170: scope = (InternationalString) subProperties.get(SCOPE_KEY);
171: this .realizationEpoch = (realizationEpoch != null) ? realizationEpoch
172: .getTime()
173: : Long.MIN_VALUE;
174: }
175:
176: /**
177: * Description, possibly including coordinates, of the point or points used to anchor the datum
178: * to the Earth. Also known as the "origin", especially for Engineering and Image Datums.
179: *
180: * <ul>
181: * <li>For a geodetic datum, this point is also known as the fundamental point, which is
182: * traditionally the point where the relationship between geoid and ellipsoid is defined.
183: * In some cases, the "fundamental point" may consist of a number of points. In those
184: * cases, the parameters defining the geoid/ellipsoid relationship have then been averaged
185: * for these points, and the averages adopted as the datum definition.</li>
186: *
187: * <li>For an engineering datum, the anchor point may be a physical point, or it may be a
188: * point with defined coordinates in another CRS.</li>
189: *
190: * <li>For an image datum, the anchor point is usually either the centre of the image or the
191: * corner of the image.</li>
192: *
193: * <li>For a temporal datum, this attribute is not defined. Instead of the anchor point,
194: * a temporal datum carries a separate time origin of type {@link Date}.</li>
195: * </ul>
196: */
197: public InternationalString getAnchorPoint() {
198: return anchorPoint;
199: }
200:
201: /**
202: * The time after which this datum definition is valid. This time may be precise (e.g. 1997
203: * for IRTF97) or merely a year (e.g. 1983 for NAD83). In the latter case, the epoch usually
204: * refers to the year in which a major recalculation of the geodetic control network, underlying
205: * the datum, was executed or initiated. An old datum can remain valid after a new datum is
206: * defined. Alternatively, a datum may be superseded by a later datum, in which case the
207: * realization epoch for the new datum defines the upper limit for the validity of the
208: * superseded datum.
209: */
210: public Date getRealizationEpoch() {
211: return (realizationEpoch != Long.MIN_VALUE) ? new Date(
212: realizationEpoch) : null;
213: }
214:
215: /**
216: * Area or region or timeframe in which this datum is valid.
217: *
218: * @since 2.4
219: */
220: public Extent getDomainOfValidity() {
221: return domainOfValidity;
222: }
223:
224: /**
225: * Area or region in which this datum object is valid.
226: *
227: * @deprecated Renamed {@link #getDomainOfValidity}.
228: */
229: public Extent getValidArea() {
230: return domainOfValidity;
231: }
232:
233: /**
234: * Description of domain of usage, or limitations of usage, for which this
235: * datum object is valid.
236: */
237: public InternationalString getScope() {
238: return scope;
239: }
240:
241: /**
242: * Gets the type of the datum as an enumerated code. Datum type was provided
243: * for all kind of datum in the legacy OGC 01-009 specification. In the new
244: * OGC 03-73 (ISO 19111) specification, datum type is provided only for
245: * vertical datum. Nevertheless, we keep this method around since it is
246: * needed for WKT formatting. Note that we returns the datum type ordinal
247: * value, not the code list object.
248: */
249: int getLegacyDatumType() {
250: return 0;
251: }
252:
253: /**
254: * Compares the specified object with this datum for equality.
255: *
256: * @param object The object to compare to {@code this}.
257: * @param compareMetadata {@code true} for performing a strict comparaison, or
258: * {@code false} for comparing only properties relevant to transformations.
259: * @return {@code true} if both objects are equal.
260: */
261: public boolean equals(final AbstractIdentifiedObject object,
262: final boolean compareMetadata) {
263: if (super .equals(object, compareMetadata)) {
264: if (!compareMetadata) {
265: /*
266: * Tests for name, since datum with different name have completly
267: * different meaning. We don't perform this comparaison if the user
268: * asked for metadata comparaison, because in such case the names
269: * have already been compared by the subclass.
270: */
271: return nameMatches(object.getName().getCode())
272: || object.nameMatches(getName().getCode());
273: }
274: final AbstractDatum that = (AbstractDatum) object;
275: return this .realizationEpoch == that.realizationEpoch
276: && Utilities.equals(this .domainOfValidity,
277: that.domainOfValidity)
278: && Utilities.equals(this .anchorPoint,
279: that.anchorPoint)
280: && Utilities.equals(this .scope, that.scope);
281: }
282: return false;
283: }
284:
285: /**
286: * Format the inner part of a
287: * <A HREF="http://geoapi.sourceforge.net/snapshot/javadoc/org/opengis/referencing/doc-files/WKT.html"><cite>Well
288: * Known Text</cite> (WKT)</A> element.
289: *
290: * Note: All subclasses will override this method, but only {@link DefaultGeodeticDatum} will
291: * <strong>not</strong> invokes this parent method, because horizontal datum do not write
292: * the datum type.
293: *
294: * @param formatter The formatter to use.
295: * @return The WKT element name.
296: */
297: protected String formatWKT(final Formatter formatter) {
298: formatter.append(getLegacyDatumType());
299: return Utilities.getShortClassName(this);
300: }
301: }
|