Mercurial > dive4elements > gnv-client
view gnv-artifacts/src/main/java/de/intevation/gnv/raster/JTSMultiPolygonProducer.java @ 813:79c1db3ca7cc
Added some more javadocs.
gnv-artifacts/trunk@897 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author | Ingo Weinzierl <ingo.weinzierl@intevation.de> |
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date | Fri, 09 Apr 2010 13:09:25 +0000 |
parents | feae2f9d6c6f |
children | f953c9a559d8 |
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package de.intevation.gnv.raster; import com.vividsolutions.jts.algorithm.CGAlgorithms; import com.vividsolutions.jts.geom.Coordinate; import com.vividsolutions.jts.geom.Geometry; import com.vividsolutions.jts.geom.GeometryFactory; import com.vividsolutions.jts.geom.LinearRing; import com.vividsolutions.jts.geom.MultiPolygon; import com.vividsolutions.jts.geom.Polygon; import com.vividsolutions.jts.geom.PrecisionModel; import com.vividsolutions.jts.geom.TopologyException; import com.vividsolutions.jts.geom.impl.PackedCoordinateSequenceFactory; import de.intevation.gnv.raster.Vectorizer.Edge; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.TreeMap; import org.apache.log4j.Logger; /** * Vectorizer backend to generated polygons in form of * JTS multi multi polygons. * * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a> */ public class JTSMultiPolygonProducer extends AbstractProducer { private static Logger log = Logger.getLogger( JTSMultiPolygonProducer.class); /** * The reference system of used coordinates: {@value} */ public static final int SRID_WGS84 = 4326; /** * Interface to decouple the conversion of the internal * index scheme of the polygons to an external one. */ public interface ValueConverter { /** * Maps integer index schemes. * @param value The input value. * @return The resulting index. */ Integer convert(Integer value); } // interface ValueConverter /** * The JTS geometry factory. */ protected GeometryFactory geometryFactory; /** * The clipping polygon. */ protected Polygon clip; /** * Internal map to map the internal polygons indices to a * list of generated polygons. */ protected HashMap<Integer, ArrayList<Polygon>> valueToPolygons; /** * Default constructor. */ public JTSMultiPolygonProducer() { } /** * Constructor to create a JTSMultiPolygonProducer with a * given clipping polygon and a world bounding box. * @param clip The clipping polygon. * @param minX Min x coord of the world. * @param minY Min y coord of the world. * @param maxX Max x coord of the world. * @param maxY Max y coord of the world. */ public JTSMultiPolygonProducer( Polygon clip, double minX, double minY, double maxX, double maxY ) { this( clip, createDefaultGeometryFactory(), minX, minY, maxX, maxY); } /** * Constructor to create a JTSMultiPolygonProducer with a * given clipping polygon, a geometry factory and a world bounding box. * @param clip The clipping polygon. * @param geometryFactory The geometry factory. * @param minX Min x coord of the world. * @param minY Min y coord of the world. * @param maxX Max x coord of the world. * @param maxY Max y coord of the world. */ public JTSMultiPolygonProducer( Polygon clip, GeometryFactory geometryFactory, double minX, double minY, double maxX, double maxY ) { super(minX, minY, maxX, maxY); this.clip = clip; this.geometryFactory = geometryFactory; valueToPolygons = new HashMap<Integer, ArrayList<Polygon>>(); } /** * Creates a 3D geometry factory via * {@link #createDefaultGeometryFactory(int)}. * @return The new geometry factory. */ public static GeometryFactory createDefaultGeometryFactory() { return createDefaultGeometryFactory(3); } /** * Creates a geometry factory with a given dimension. * @param dim The dimension. * @return The new geometry factory. */ public static GeometryFactory createDefaultGeometryFactory(int dim) { return new GeometryFactory( new PrecisionModel( PrecisionModel.FLOATING), SRID_WGS84, new PackedCoordinateSequenceFactory( PackedCoordinateSequenceFactory.DOUBLE, dim)); } public void handleRings( List<Edge> rings, int value, int width, int height ) { if (value == -1) { return; } double b1 = minX; double m1 = width != 1 ? (maxX - minX)/(width-1) : 0d; double b2 = minY; double m2 = height != 1 ? (maxY - minY)/(height-1) : 0d; ArrayList<Coordinate> vertices = new ArrayList<Coordinate>(); LinearRing shell = null; ArrayList<LinearRing> holes = new ArrayList<LinearRing>(); for (Edge head: rings) { Edge current = head; do { vertices.add(new Coordinate( m1*(current.a % width) + b1, m2*(current.a / width) + b2)); } while ((current = current.prev) != head); vertices.add(new Coordinate( m1*(head.a % width) + b1, m2*(head.a / width) + b2)); Coordinate [] coordinates = vertices.toArray(new Coordinate[vertices.size()]); vertices.clear(); LinearRing ring = geometryFactory.createLinearRing( coordinates); if (CGAlgorithms.isCCW(coordinates)) { shell = ring; } else { holes.add(ring); } } if (shell == null) { log.error("polygon has no shell"); return; } Polygon polygon = geometryFactory.createPolygon( shell, holes.toArray(new LinearRing[holes.size()])); if (clip == null || clip.intersects(polygon)) { Integer v = Integer.valueOf(value); ArrayList<Polygon> polygons = valueToPolygons.get(v); if (polygons == null) { valueToPolygons.put(v, polygons = new ArrayList<Polygon>()); } polygons.add(polygon); } } /** * Returns a index -> multi polyon map. The internal index scheme * is retained. * {@link #getMultiPolygons(de.intevation.gnv.raster.JTSMultiPolygonProducer.ValueConverter)} * @return The new map. */ public Map<Integer, MultiPolygon> getMultiPolygons() { return getMultiPolygons(null); } /** * Flattend a JTS geometry to a multi polygon if possible * @param result The geometry to be flattend * @return The resulting multi polygon. */ protected MultiPolygon flattenCollection(Geometry result) { if (result instanceof MultiPolygon) { return (MultiPolygon)result; } if (result instanceof Polygon) { return geometryFactory.createMultiPolygon( new Polygon[] { (Polygon)result }); } log.warn("cannot handle " + result.getClass()); return null; } /** * Returns a index -> multi polyon map. The internal index scheme * is remapped with the given value converter. * @param valueConverter Converter to remap the index scheme. Maybe null * if no remapping is required. * @return The new map. */ public Map<Integer, MultiPolygon> getMultiPolygons( ValueConverter valueConverter ) { TreeMap<Integer, MultiPolygon> multiPolygons = new TreeMap<Integer, MultiPolygon>(); for (Map.Entry<Integer, ArrayList<Polygon>> entry: valueToPolygons.entrySet() ) { ArrayList<Polygon> polygons = entry.getValue(); Integer value = valueConverter != null ? valueConverter.convert(entry.getKey()) : entry.getKey(); MultiPolygon mp = geometryFactory.createMultiPolygon( polygons.toArray(new Polygon[polygons.size()])); if (clip != null) { try { Geometry result = mp.intersection(clip); MultiPolygon mp2 = flattenCollection(result); if (mp2 != null) { mp = mp2; } } catch (TopologyException te) { log.error(te.getLocalizedMessage(), te); } } multiPolygons.put(value, mp); } return multiPolygons; } /** * Empties internal temporary data structures to save some memory. */ public void clear() { valueToPolygons.clear(); } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :