Introduce GIS utilities.

[gpl/argeo-suite.git] / org.argeo.app.core / src / org / argeo / app / geo / GpxUtils.java

diff --git a/org.argeo.app.core/src/org/argeo/app/geo/GpxUtils.java b/org.argeo.app.core/src/org/argeo/app/geo/GpxUtils.java
new file mode 100644 (file)
index 0000000..be028d3
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+++ b/org.argeo.app.core/src/org/argeo/app/geo/GpxUtils.java
@@ -0,0 +1,68 @@
+package org.argeo.app.geo;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.parsers.SAXParser;
+import javax.xml.parsers.SAXParserFactory;
+
+import org.geotools.data.DataUtilities;
+import org.geotools.feature.SchemaException;
+import org.geotools.feature.simple.SimpleFeatureBuilder;
+import org.geotools.geometry.jts.JTSFactoryFinder;
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.GeometryFactory;
+import org.locationtech.jts.geom.Polygon;
+import org.opengis.feature.simple.SimpleFeature;
+import org.opengis.feature.simple.SimpleFeatureType;
+import org.xml.sax.Attributes;
+import org.xml.sax.SAXException;
+import org.xml.sax.helpers.DefaultHandler;
+
+/** Utilities around the GPX format. */
+public class GpxUtils {
+
+       public static SimpleFeature parseGpxToPolygon(InputStream in) {
+               try {
+                       final SimpleFeatureType TYPE = DataUtilities.createType("Area", "the_geom:Polygon:srid=4326");
+                       SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);
+
+                       GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
+                       List<Coordinate> coordinates = new ArrayList<>();
+                       SAXParserFactory factory = SAXParserFactory.newInstance();
+                       Double[] startCoord = new Double[2];
+                       SAXParser saxParser = factory.newSAXParser();
+
+                       saxParser.parse(in, new DefaultHandler() {
+
+                               @Override
+                               public void startElement(String uri, String localName, String qName, Attributes attributes)
+                                               throws SAXException {
+                                       if ("trkpt".equals(qName)) {
+                                               Double latitude = Double.parseDouble(attributes.getValue("lat"));
+                                               Double longitude = Double.parseDouble(attributes.getValue("lon"));
+                                               Coordinate coordinate = new Coordinate(longitude, latitude);
+                                               coordinates.add(coordinate);
+                                       }
+                               }
+
+                       });
+                       // close the line string
+                       coordinates.add(coordinates.get(0));
+
+                       Polygon polygon = geometryFactory.createPolygon(coordinates.toArray(new Coordinate[coordinates.size()]));
+                       featureBuilder.add(polygon);
+                       SimpleFeature area = featureBuilder.buildFeature(null);
+                       return area;
+               } catch (ParserConfigurationException | SAXException | IOException | SchemaException e) {
+                       throw new RuntimeException("Cannot convert GPX", e);
+               }
+       }
+
+       /** Singleton. */
+       private GpxUtils() {
+       }
+}