--- /dev/null
+package org.argeo.app.geo;
+
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Envelope;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.GeometryCollection;
+import org.locationtech.jts.geom.LineString;
+import org.locationtech.jts.geom.LinearRing;
+import org.locationtech.jts.geom.MultiPoint;
+import org.locationtech.jts.geom.Point;
+import org.locationtech.jts.geom.Polygon;
+
+import jakarta.json.JsonArray;
+import jakarta.json.JsonObject;
+import jakarta.json.stream.JsonGenerator;
+
+/**
+ * GeoJSon format.
+ *
+ * @see https://datatracker.ietf.org/doc/html/rfc7946
+ */
+public class GeoJson {
+ public final static String POINT_TYPE = "Point";
+ public final static String MULTI_POINT_TYPE = "MultiPoint";
+ public final static String LINE_STRING_TYPE = "LineString";
+ public final static String POLYGON_TYPE = "Polygon";
+ public final static String GEOMETRY_COLLECTION_TYPE = "GeometryCollection";
+
+ public final static String TYPE = "type";
+ public final static String GEOMETRY = "geometry";
+ public final static String GEOMETRIES = "geometries";
+ public final static String COORDINATES = "coordinates";
+ public final static String BBOX = "bbox";
+ public final static String PROPERTIES = "properties";
+
+ /*
+ * WRITE
+ */
+ /** Writes a {@link Geometry} as GeoJSON. */
+ public static void writeGeometry(JsonGenerator g, Geometry geometry) {
+ if (geometry instanceof Point point) {
+ g.write(TYPE, POINT_TYPE);
+ g.writeStartArray(COORDINATES);
+ writeCoordinate(g, point.getCoordinate());
+ g.writeEnd();// coordinates array
+ } else if (geometry instanceof MultiPoint multiPoint) {
+ g.write(TYPE, MULTI_POINT_TYPE);
+ g.writeStartArray(COORDINATES);
+ writeCoordinates(g, multiPoint.getCoordinates());
+ g.writeEnd();// coordinates array
+ } else if (geometry instanceof LineString lineString) {
+ g.write(TYPE, LINE_STRING_TYPE);
+ g.writeStartArray(COORDINATES);
+ writeCoordinates(g, lineString.getCoordinates());
+ g.writeEnd();// coordinates array
+ } else if (geometry instanceof Polygon polygon) {
+ g.write(TYPE, POLYGON_TYPE);
+ g.writeStartArray(COORDINATES);
+ LinearRing exteriorRing = polygon.getExteriorRing();
+ g.writeStartArray();
+ writeCoordinates(g, exteriorRing.getCoordinates());
+ g.writeEnd();
+ for (int i = 0; i < polygon.getNumInteriorRing(); i++) {
+ LinearRing interiorRing = polygon.getInteriorRingN(i);
+ // TODO verify that holes are clockwise
+ g.writeStartArray();
+ writeCoordinates(g, interiorRing.getCoordinates());
+ g.writeEnd();
+ }
+ g.writeEnd();// coordinates array
+ } else if (geometry instanceof GeometryCollection geometryCollection) {// must be last
+ g.write(TYPE, GEOMETRY_COLLECTION_TYPE);
+ g.writeStartArray(GEOMETRIES);
+ for (int i = 0; i < geometryCollection.getNumGeometries(); i++) {
+ g.writeStartObject();
+ writeGeometry(g, geometryCollection.getGeometryN(i));
+ g.writeEnd();// geometry object
+ }
+ g.writeEnd();// geometries array
+ } else {
+ throw new IllegalArgumentException(geometry.getClass() + " is not supported.");
+ }
+ }
+
+ /** Writes a sequence of coordinates [[lat,lon],[lat,lon]] */
+ public static void writeCoordinates(JsonGenerator g, Coordinate[] coordinates) {
+ for (Coordinate coordinate : coordinates) {
+ g.writeStartArray();
+ writeCoordinate(g, coordinate);
+ g.writeEnd();
+ }
+ }
+
+ /** Writes a pair of coordinates [lat,lon]. */
+ public static void writeCoordinate(JsonGenerator g, Coordinate coordinate) {
+ g.write(coordinate.getX());
+ g.write(coordinate.getY());
+ double z = coordinate.getZ();
+ if (!Double.isNaN(z)) {
+ g.write(z);
+ }
+ }
+
+ /**
+ * Writes the {@link Envelope} of a {@link Geometry} as a bbox GeoJSON object.
+ */
+ public static void writeBBox(JsonGenerator g, Geometry geometry) {
+ g.writeStartArray(BBOX);
+ Envelope envelope = geometry.getEnvelopeInternal();
+ g.write(envelope.getMinX());
+ g.write(envelope.getMinY());
+ g.write(envelope.getMaxX());
+ g.write(envelope.getMaxY());
+ g.writeEnd();
+ }
+
+ /*
+ * READ
+ */
+ /** Reads a geometry from the geometry object of a GEoJSON feature. */
+ @SuppressWarnings("unchecked")
+ public static <T extends Geometry> T readGeometry(JsonObject geom, Class<T> clss) {
+ String type = geom.getString(TYPE);
+ JsonArray coordinates = geom.getJsonArray(COORDINATES);
+ Geometry res = switch (type) {
+ case POINT_TYPE: {
+ Coordinate coord = readCoordinate(coordinates);
+ yield JTS.GEOMETRY_FACTORY_WGS84.createPoint(coord);
+ }
+ case LINE_STRING_TYPE: {
+ Coordinate[] coords = readCoordinates(coordinates);
+ yield JTS.GEOMETRY_FACTORY_WGS84.createLineString(coords);
+ }
+ case POLYGON_TYPE: {
+ assert coordinates.size() > 0;
+ LinearRing exterior = JTS.GEOMETRY_FACTORY_WGS84
+ .createLinearRing(readCoordinates(coordinates.getJsonArray(0)));
+ LinearRing[] holes = new LinearRing[coordinates.size() - 1];
+ for (int i = 0; i < coordinates.size() - 1; i++) {
+ holes[i] = JTS.GEOMETRY_FACTORY_WGS84
+ .createLinearRing(readCoordinates(coordinates.getJsonArray(i + 1)));
+ }
+ yield JTS.GEOMETRY_FACTORY_WGS84.createPolygon(exterior, holes);
+ }
+ default:
+ throw new IllegalArgumentException("Unexpected value: " + type);
+ };
+// res.normalize();
+ return (T) res;
+ }
+
+ /** Reads a coordinate sequence [[lat,lon],[lat,lon]]. */
+ public static Coordinate readCoordinate(JsonArray arr) {
+ assert arr.size() >= 2;
+ return new Coordinate(arr.getJsonNumber(0).doubleValue(), arr.getJsonNumber(1).doubleValue());
+ }
+
+ /** Reads a coordinate pair [lat,lon]. */
+ public static Coordinate[] readCoordinates(JsonArray arr) {
+ Coordinate[] coords = new Coordinate[arr.size()];
+ for (int i = 0; i < arr.size(); i++)
+ coords[i] = readCoordinate(arr.getJsonArray(i));
+ return coords;
+ }
+
+ /** singleton */
+ private GeoJson() {
+ }
+
+}
projects / gpl / argeo-suite.git / blobdiff