X-Git-Url: http://git.argeo.org/?a=blobdiff_plain;f=org.argeo.app.geo%2Fsrc%2Forg%2Fargeo%2Fapp%2Fgeo%2FGeoJSon.java;h=5d5b99fdeb32efd6a29b84d665455e5170cc38e0;hb=8b7dc8398a17d09c5e20857b4e1e5f82ad28e769;hp=b590814ee2961113799111297ad60839691ac87f;hpb=8a490e540ac623b3545b1bd3da65ecbf2e4b6436;p=gpl%2Fargeo-suite.git

diff --git a/org.argeo.app.geo/src/org/argeo/app/geo/GeoJSon.java b/org.argeo.app.geo/src/org/argeo/app/geo/GeoJSon.java
index b590814..5d5b99f 100644
--- a/org.argeo.app.geo/src/org/argeo/app/geo/GeoJSon.java
+++ b/org.argeo.app.geo/src/org/argeo/app/geo/GeoJSon.java
@@ -8,6 +8,8 @@ import org.locationtech.jts.geom.LinearRing;
 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;
 
 /**
@@ -16,31 +18,34 @@ import jakarta.json.stream.JsonGenerator;
  * @see https://datatracker.ietf.org/doc/html/rfc7946
  */
 public class GeoJSon {
-	public static void writeBBox(JsonGenerator generator, Geometry geometry) {
-		generator.writeStartArray("bbox");
-		Envelope envelope = geometry.getEnvelopeInternal();
-		generator.write(envelope.getMinX());
-		generator.write(envelope.getMinY());
-		generator.write(envelope.getMaxX());
-		generator.write(envelope.getMaxY());
-		generator.writeEnd();
-	}
+	public final static String POINT_TYPE = "Point";
+	public final static String LINE_STRING_TYPE = "LineString";
+	public final static String POLYGON_TYPE = "Polygon";
+
+	public final static String TYPE = "type";
+	public final static String GEOMETRY = "geometry";
+	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 generator, Geometry geometry) {
-		generator.writeStartObject("geometry");
 		if (geometry instanceof Point point) {
-			generator.write("type", "Point");
-			generator.writeStartArray("coordinates");
+			generator.write(TYPE, POINT_TYPE);
+			generator.writeStartArray(COORDINATES);
 			writeCoordinate(generator, point.getCoordinate());
 			generator.writeEnd();// coordinates array
 		} else if (geometry instanceof LineString lineString) {
-			generator.write("type", "LineString");
-			generator.writeStartArray("coordinates");
+			generator.write(TYPE, LINE_STRING_TYPE);
+			generator.writeStartArray(COORDINATES);
 			writeCoordinates(generator, lineString.getCoordinates());
 			generator.writeEnd();// coordinates array
 		} else if (geometry instanceof Polygon polygon) {
-			generator.write("type", "Polygon");
-			generator.writeStartArray("coordinates");
+			generator.write(TYPE, POLYGON_TYPE);
+			generator.writeStartArray(COORDINATES);
 			LinearRing exteriorRing = polygon.getExteriorRing();
 			generator.writeStartArray();
 			writeCoordinates(generator, exteriorRing.getCoordinates());
@@ -54,9 +59,9 @@ public class GeoJSon {
 			}
 			generator.writeEnd();// coordinates array
 		}
-		generator.writeEnd();// geometry object
 	}
 
+	/** Writes a sequence of coordinates [[lat,lon],[lat,lon]] */
 	public static void writeCoordinates(JsonGenerator generator, Coordinate[] coordinates) {
 		for (Coordinate coordinate : coordinates) {
 			generator.writeStartArray();
@@ -65,6 +70,7 @@ public class GeoJSon {
 		}
 	}
 
+	/** Writes a pair of coordinates [lat,lon]. */
 	public static void writeCoordinate(JsonGenerator generator, Coordinate coordinate) {
 		generator.write(coordinate.getX());
 		generator.write(coordinate.getY());
@@ -74,6 +80,68 @@ public class GeoJSon {
 		}
 	}
 
+	/**
+	 * Writes the {@link Envelope} of a {@link Geometry} as a bbox GeoJSON object.
+	 */
+	public static void writeBBox(JsonGenerator generator, Geometry geometry) {
+		generator.writeStartArray(BBOX);
+		Envelope envelope = geometry.getEnvelopeInternal();
+		generator.write(envelope.getMinX());
+		generator.write(envelope.getMinY());
+		generator.write(envelope.getMaxX());
+		generator.write(envelope.getMaxY());
+		generator.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() {
 	}