RegionChooser: ConvexHullCalculator from Citygml in local coordinates.

src/eu/simstadt/regionchooser/ConvexHullCalculator.java

+package eu.simstadt.regionchooser;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import com.vividsolutions.jts.algorithm.ConvexHull;
+import com.vividsolutions.jts.geom.Coordinate;
+import com.vividsolutions.jts.geom.Geometry;
+import com.vividsolutions.jts.geom.GeometryFactory;
+import com.ximpleware.NavException;
+import com.ximpleware.XPathEvalException;
+import com.ximpleware.XPathParseException;
+import eu.simstadt.regionchooser.citygml_parser.BuildingXmlNode;
+import eu.simstadt.regionchooser.citygml_parser.CityGmlIterator;
+
+
+public class ConvexHullCalculator
+{
+	//TODO: Convert coordinates to WGS84
+	public static Geometry calculateFromCityGML(Path citygmlPath)
+			throws NumberFormatException, XPathParseException, NavException, XPathEvalException, IOException {
+
+		ArrayList<Coordinate> allPoints = new ArrayList<Coordinate>();
+		CityGmlIterator citygml = new CityGmlIterator(citygmlPath);
+		for (BuildingXmlNode buildingXmlNode : citygml) {
+			allPoints.add(new Coordinate(buildingXmlNode.xMin, buildingXmlNode.yMin));
+			allPoints.add(new Coordinate(buildingXmlNode.xMin, buildingXmlNode.yMax));
+			allPoints.add(new Coordinate(buildingXmlNode.xMax, buildingXmlNode.yMin));
+			allPoints.add(new Coordinate(buildingXmlNode.xMax, buildingXmlNode.yMax));
+		}
+
+		ConvexHull ch = new com.vividsolutions.jts.algorithm.ConvexHull(
+				allPoints.toArray(new Coordinate[allPoints.size()]), new GeometryFactory());
+		return ch.getConvexHull();
+	}
+
+}

src/eu/simstadt/regionchooser/RegionExtractor.java

@@ -20,7 +20,7 @@
 
 public class RegionExtractor
 {
-	static private WKTReader wktReader = new WKTReader();
+	private static final WKTReader wktReader = new WKTReader();
 
 	private static final Logger LOGGER = Logger.getLogger(RegionExtractor.class.getName());
 	private static final GeometryFactory gf = new GeometryFactory();

test/eu/simstadt/regionchooser/test/ConvexHullCalculatorTests.java

+package eu.simstadt.regionchooser.test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import org.junit.Test;
+import com.vividsolutions.jts.geom.Coordinate;
+import com.vividsolutions.jts.geom.Geometry;
+import com.vividsolutions.jts.geom.GeometryFactory;
+import com.vividsolutions.jts.geom.Point;
+import eu.simstadt.regionchooser.ConvexHullCalculator;
+
+
+public class ConvexHullCalculatorTests
+{
+	private static final GeometryFactory gf = new GeometryFactory();
+
+	@Test
+	public void testExtractConvexHullFromOneBuilding() throws Throwable {
+		Path repo = Paths.get("../TestRepository");
+		Path citygmlPath = repo.resolve("Gruenbuehl.proj/20140218_Gruenbuehl_LOD2_1building.gml");
+		Geometry hull = ConvexHullCalculator.calculateFromCityGML(citygmlPath);
+		assertEquals(hull.getCoordinates().length, 4 + 1); // Convex hull of a building should be a closed rectangle
+		Point someBuildingPoint = gf.createPoint(new Coordinate(3515960.36, 5415667.91));
+		assertTrue(hull.contains(someBuildingPoint));
+	}
+
+	@Test
+	public void testExtractConvexHullFromOneSmallRegion() throws Throwable {
+		Path repo = Paths.get("../TestRepository");
+		Path citygmlPath = repo.resolve("Gruenbuehl.proj/Gruenbuehl_LOD2_ALKIS_1010.gml");
+		Geometry hull = ConvexHullCalculator.calculateFromCityGML(citygmlPath);
+		assertTrue(hull.getCoordinates().length > 4); // Convex hull should have at least 4 corners
+		Point somewhereBetweenBuildings = gf.createPoint(new Coordinate(3515883.6668538367, 5415843.300640578));
+		assertTrue(hull.contains(somewhereBetweenBuildings));
+	}
+}