RegionChooser: Fast extractor of CoordinateReferenceSystem

src/eu/simstadt/regionchooser/citygml_parser/CityGmlIterator.java

@@ -4,13 +4,18 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Iterator;
+import java.util.Optional;
 import java.util.logging.Logger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import org.osgeo.proj4j.CoordinateReferenceSystem;
 import com.ximpleware.AutoPilot;
 import com.ximpleware.NavException;
 import com.ximpleware.VTDGen;
 import com.ximpleware.VTDNav;
 import com.ximpleware.XPathEvalException;
 import com.ximpleware.XPathParseException;
+import eu.simstadt.geo.GeoUtils;
 
 
 public class CityGmlIterator implements Iterable<BuildingXmlNode>
@@ -23,6 +28,7 @@ public class CityGmlIterator implements Iterable<BuildingXmlNode>
 	private int buildingOffset = 0;
 	private int buildingLength = 0;
 	private Path citygmlPath;
+	private Pattern srsNamePattern = Pattern.compile("(?i)(?<=srsName=\")[^\"]+(?=\")");
 
 	/*
 	 * Simple class to parse a CityGML and extract cityObjectMember XML nodes and their coordinates. Since the
@@ -39,7 +45,7 @@ public CityGmlIterator(Path citygmlPath)
 		parser.parseFile(citygmlPath.toString(), false);
 		this.navigator = parser.getNav();
 		this.buildingsFinder = new AutoPilot(navigator);
-		buildingsFinder.selectXPath("/CityModel/cityObjectMember[Building]"); //TODO: Check it's the only correct possibility
+		buildingsFinder.selectXPath("/CityModel/cityObjectMember[Building]"); //TODO: Check it's the only correct possibility. //FIXME: BuildingPart too!
 	}
 
 	@Override
@@ -87,4 +93,18 @@ public Object getFooter() throws IOException, NavException {
 		return navigator.toRawString(footerOffset, footerLength);
 	}
 
+	/*
+	 * Fast scan of the 50 first lines to look for srsName
+	 * 
+	 */
+	public CoordinateReferenceSystem getCRS() throws IOException {
+		Optional<String> line = Files.lines(citygmlPath).limit(50).filter(srsNamePattern.asPredicate()).findFirst();
+		if (line.isPresent()) {
+			Matcher matcher = srsNamePattern.matcher(line.get());
+			matcher.find();
+			return GeoUtils.crsFromSrsName(matcher.group());
+		} else {
+			throw new IllegalArgumentException("No srsName found in the header of " + citygmlPath);
+		}
+	}
 }

test/eu/simstadt/regionchooser/test/CitygmlParserTests.java

 package eu.simstadt.regionchooser.test;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import java.io.IOException;
@@ -15,9 +16,10 @@
 
 public class CitygmlParserTests
 {
-	private void testNoNanInCoordinates(Path citygmlPath)
+	private void testCRSandNoNanInCoordinates(Path citygmlPath, String crsName)
 			throws NumberFormatException, XPathParseException, NavException, XPathEvalException, IOException {
 		CityGmlIterator buildingXmlNodes = new CityGmlIterator(citygmlPath);
+		assertEquals(crsName, buildingXmlNodes.getCRS().toString());
 		for (BuildingXmlNode buildingXmlNode : buildingXmlNodes) {
 			assertFalse("Coordinate should be a double", Double.isNaN(buildingXmlNode.x));
 			assertFalse("Coordinate should be a double", Double.isNaN(buildingXmlNode.y));
@@ -30,7 +32,6 @@ private void testNoNanInCoordinates(Path citygmlPath)
 			assertTrue("Coordinates Min/Max should be plausible", buildingXmlNode.xMin < buildingXmlNode.x);
 			assertTrue("Coordinates Min/Max should be plausible", buildingXmlNode.yMin < buildingXmlNode.y);
 		}
-
 	}
 
 	@Test
@@ -38,20 +39,27 @@ public void testExtractCoordsFromStuttgart()
 			throws NumberFormatException, XPathParseException, NavException, XPathEvalException, IOException {
 		Path repo = Paths.get("../TestRepository");
 		Path citygmlPath = repo.resolve("Stuttgart.proj/Stuttgart_LOD0_LOD1_buildings_and_trees.gml");
-		testNoNanInCoordinates(citygmlPath);
+		testCRSandNoNanInCoordinates(citygmlPath, "EPSG:31467");
 	}
 
 	@Test
 	public void testExtractCoordsFromGruenbuehl() throws Throwable {
 		Path repo = Paths.get("../TestRepository");
 		Path citygmlPath = repo.resolve("Gruenbuehl.proj/20140218_Gruenbuehl_LOD2_1building.gml");
-		testNoNanInCoordinates(citygmlPath);
+		testCRSandNoNanInCoordinates(citygmlPath, "EPSG:31467");
 	}
 
 	@Test
 	public void testExtractCoordsFromMunich() throws Throwable {
 		Path repo = Paths.get("../TestRepository");
 		Path citygmlPath = repo.resolve("Muenchen.proj/Munich_v_1_0_0.gml");
-		testNoNanInCoordinates(citygmlPath);
+		testCRSandNoNanInCoordinates(citygmlPath, "EPSG:32632");
+	}
+
+	@Test
+	public void testExtractCoordsFromNYC() throws Throwable {
+		Path repo = Paths.get("../TestRepository");
+		Path citygmlPath = repo.resolve("NewYork.proj/ManhattanSmall.gml");
+		testCRSandNoNanInCoordinates(citygmlPath, "EPSG:32118");
 	}
 }