/**
* H2GIS is a library that brings spatial support to the H2 Database Engine
* <http://www.h2database.com>. H2GIS is developed by CNRS
* <http://www.cnrs.fr/>.
*
* This code is part of the H2GIS project. H2GIS is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* Lesser General Public License as published by the Free Software Foundation;
* version 3.0 of the License.
*
* H2GIS is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details <http://www.gnu.org/licenses/>.
*
*
* For more information, please consult: <http://www.h2gis.org/>
* or contact directly: info_at_h2gis.org
*/
package org.h2gis.functions.io.geojson;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryCollection;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.geom.LinearRing;
import com.vividsolutions.jts.geom.MultiLineString;
import com.vividsolutions.jts.geom.MultiPoint;
import com.vividsolutions.jts.geom.MultiPolygon;
import com.vividsolutions.jts.geom.Point;
import com.vividsolutions.jts.geom.Polygon;
import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;
/**
* This class is used to convert a geojon geometry to a JTS geometry.
*
* @author Erwan Bocher
*/
public class GJGeometryReader {
private final GeometryFactory GF;
public GJGeometryReader(GeometryFactory GF) {
this.GF=GF;
}
/**
* Parses a GeoJSON geometry and returns its JTS representation.
*
* Syntax:
*
* "geometry":{"type": "Point", "coordinates": [102.0,0.5]}
*
* @param jsParser
* @throws IOException
* @return Geometry
* @throws java.sql.SQLException
*/
public Geometry parseGeometry(JsonParser jsParser) throws IOException, SQLException {
jsParser.nextToken(); // START_OBJECT {
jsParser.nextToken(); // FIELD_NAME type
jsParser.nextToken(); // VALUE_STRING Point or whatever supported
String geomType = jsParser.getText();
if (geomType.equalsIgnoreCase(GeoJsonField.POINT)) {
return parsePoint(jsParser);
} else if (geomType.equalsIgnoreCase(GeoJsonField.MULTIPOINT)) {
return parseMultiPoint(jsParser);
} else if (geomType.equalsIgnoreCase(GeoJsonField.LINESTRING)) {
return parseLinestring(jsParser);
} else if (geomType.equalsIgnoreCase(GeoJsonField.MULTILINESTRING)) {
return parseMultiLinestring(jsParser);
} else if (geomType.equalsIgnoreCase(GeoJsonField.POLYGON)) {
return parsePolygon(jsParser);
} else if (geomType.equalsIgnoreCase(GeoJsonField.MULTIPOLYGON)) {
return parseMultiPolygon(jsParser);
} else if (geomType.equalsIgnoreCase(GeoJsonField.GEOMETRYCOLLECTION)) {
return parseGeometryCollection(jsParser);
} else {
throw new SQLException("Unsupported geometry : " + geomType);
}
}
/**
* Parses one position
*
* Syntax:
*
* { "type": "Point", "coordinates": [100.0, 0.0] }
*
* @param jsParser
* @throws IOException
* @return Point
*/
private Point parsePoint(JsonParser jp) throws IOException, SQLException {
jp.nextToken(); // FIELD_NAME coordinates
String coordinatesField = jp.getText();
if (coordinatesField.equalsIgnoreCase(GeoJsonField.COORDINATES)) {
jp.nextToken(); // START_ARRAY [ to parse the coordinate
Point point = GF.createPoint(parseCoordinate(jp));
jp.nextToken();
return point;
} else {
throw new SQLException("Malformed GeoJSON file. Expected 'coordinates', found '" + coordinatesField + "'");
}
}
/**
* Parses an array of positions
*
* Syntax:
*
* { "type": "MultiPoint", "coordinates": [ [100.0, 0.0], [101.0, 1.0] ] }
*
* @param jsParser
* @throws IOException
* @return MultiPoint
*/
private MultiPoint parseMultiPoint(JsonParser jp) throws IOException, SQLException {
jp.nextToken(); // FIELD_NAME coordinates
String coordinatesField = jp.getText();
if (coordinatesField.equalsIgnoreCase(GeoJsonField.COORDINATES)) {
jp.nextToken(); // START_ARRAY [ coordinates
MultiPoint mPoint = GF.createMultiPoint(parseCoordinates(jp));
jp.nextToken();//END_OBJECT } geometry
return mPoint;
} else {
throw new SQLException("Malformed GeoJSON file. Expected 'coordinates', found '" + coordinatesField + "'");
}
}
/**
*
* Parse the array of positions.
*
* Syntax:
*
* { "type": "LineString", "coordinates": [ [100.0, 0.0], [101.0, 1.0] ] }
*
* @param jsParser
*/
private LineString parseLinestring(JsonParser jp) throws IOException, SQLException {
jp.nextToken(); // FIELD_NAME coordinates
String coordinatesField = jp.getText();
if (coordinatesField.equalsIgnoreCase(GeoJsonField.COORDINATES)) {
jp.nextToken(); // START_ARRAY [ coordinates
LineString line = GF.createLineString(parseCoordinates(jp));
jp.nextToken();//END_OBJECT } geometry
return line;
} else {
throw new SQLException("Malformed GeoJSON file. Expected 'coordinates', found '" + coordinatesField + "'");
}
}
/**
* Parses an array of positions defined as:
*
* { "type": "MultiLineString", "coordinates": [ [ [100.0, 0.0], [101.0,
* 1.0] ], [ [102.0, 2.0], [103.0, 3.0] ] ] }
*
* @param jsParser
* @return MultiLineString
*/
private MultiLineString parseMultiLinestring(JsonParser jp) throws IOException, SQLException {
jp.nextToken(); // FIELD_NAME coordinates
String coordinatesField = jp.getText();
if (coordinatesField.equalsIgnoreCase(GeoJsonField.COORDINATES)) {
ArrayList<LineString> lineStrings = new ArrayList<LineString>();
jp.nextToken();//START_ARRAY [ coordinates
jp.nextToken(); // START_ARRAY [ coordinates line
while (jp.getCurrentToken() != JsonToken.END_ARRAY) {
lineStrings.add(GF.createLineString(parseCoordinates(jp)));
jp.nextToken();
}
MultiLineString line = GF.createMultiLineString(lineStrings.toArray(new LineString[lineStrings.size()]));
jp.nextToken();//END_OBJECT } geometry
return line;
} else {
throw new SQLException("Malformed GeoJSON file. Expected 'coordinates', found '" + coordinatesField + "'");
}
}
/**
* Coordinates of a Polygon are an array of LinearRing coordinate arrays.
* The first element in the array represents the exterior ring. Any
* subsequent elements represent interior rings (or holes).
*
* Syntax:
*
* No holes:
*
* { "type": "Polygon", "coordinates": [ [ [100.0, 0.0], [101.0, 0.0],
* [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ] ] }
*
* With holes:
*
* { "type": "Polygon", "coordinates": [ [ [100.0, 0.0], [101.0, 0.0],
* [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ], [ [100.2, 0.2], [100.8, 0.2],
* [100.8, 0.8], [100.2, 0.8], [100.2, 0.2] ] ] }
*
*
*
* @param jp
* @return Polygon
*/
private Polygon parsePolygon(JsonParser jp) throws IOException, SQLException {
jp.nextToken(); // FIELD_NAME coordinates
String coordinatesField = jp.getText();
if (coordinatesField.equalsIgnoreCase(GeoJsonField.COORDINATES)) {
jp.nextToken(); // START_ARRAY [ coordinates
jp.nextToken(); //Start the RING
int linesIndex = 0;
LinearRing linearRing = null;
ArrayList<LinearRing> holes = new ArrayList<LinearRing>();
while (jp.getCurrentToken() != JsonToken.END_ARRAY) {
if (linesIndex == 0) {
linearRing = GF.createLinearRing(parseCoordinates(jp));
} else {
holes.add(GF.createLinearRing(parseCoordinates(jp)));
}
jp.nextToken();//END RING
linesIndex++;
}
if (linesIndex > 1) {
jp.nextToken();//END_OBJECT } geometry
return GF.createPolygon(linearRing, holes.toArray(new LinearRing[holes.size()]));
} else {
jp.nextToken();//END_OBJECT } geometry
return GF.createPolygon(linearRing, null);
}
} else {
throw new SQLException("Malformed GeoJSON file. Expected 'coordinates', found '" + coordinatesField + "'");
}
}
/**
* Coordinates of a MultiPolygon are an array of Polygon coordinate arrays:
*
* { "type": "MultiPolygon", "coordinates": [ [[[102.0, 2.0], [103.0, 2.0],
* [103.0, 3.0], [102.0, 3.0], [102.0, 2.0]]], [[[100.0, 0.0], [101.0, 0.0],
* [101.0, 1.0], [100.0, 1.0], [100.0, 0.0]], [[100.2, 0.2], [100.8, 0.2],
* [100.8, 0.8], [100.2, 0.8], [100.2, 0.2]]] ] }
*
* @param jp
* @throws IOException
* @throws SQLException
* @return MultiPolygon
*/
private MultiPolygon parseMultiPolygon(JsonParser jp) throws IOException, SQLException {
jp.nextToken(); // FIELD_NAME coordinates
String coordinatesField = jp.getText();
if (coordinatesField.equalsIgnoreCase(GeoJsonField.COORDINATES)) {
ArrayList<Polygon> polygons = new ArrayList<Polygon>();
jp.nextToken(); // START_ARRAY [ coordinates
jp.nextToken(); //Start the polygon
while (jp.getCurrentToken() != JsonToken.END_ARRAY) {
//Parse the polygon
jp.nextToken(); //Start the RING
int linesIndex = 0;
LinearRing linearRing = null;
ArrayList<LinearRing> holes = new ArrayList<LinearRing>();
while (jp.getCurrentToken() != JsonToken.END_ARRAY) {
if (linesIndex == 0) {
linearRing = GF.createLinearRing(parseCoordinates(jp));
} else {
holes.add(GF.createLinearRing(parseCoordinates(jp)));
}
jp.nextToken();//END RING
linesIndex++;
}
if (linesIndex > 1) {
jp.nextToken();//END_OBJECT
polygons.add(GF.createPolygon(linearRing, holes.toArray(new LinearRing[holes.size()])));
} else {
jp.nextToken();//END_OBJECT
polygons.add(GF.createPolygon(linearRing, null));
}
}
jp.nextToken();//END_OBJECT } geometry
return GF.createMultiPolygon(polygons.toArray(new Polygon[polygons.size()]));
} else {
throw new SQLException("Malformed GeoJSON file. Expected 'coordinates', found '" + coordinatesField + "'");
}
}
/**
* Each element in the geometries array of a GeometryCollection is one of
* the geometry objects described above:
*
* { "type": "GeometryCollection", "geometries": [ { "type": "Point",
* "coordinates": [100.0, 0.0] }, { "type": "LineString", "coordinates": [
* [101.0, 0.0], [102.0, 1.0] ] } ]}
*
* @param jp
*
* @throws IOException
* @throws SQLException
* @return GeometryCollection
*/
private GeometryCollection parseGeometryCollection(JsonParser jp) throws IOException, SQLException {
jp.nextToken(); // FIELD_NAME geometries
String coordinatesField = jp.getText();
if (coordinatesField.equalsIgnoreCase(GeoJsonField.GEOMETRIES)) {
jp.nextToken();//START array
//jp.nextToken();//START object
ArrayList<Geometry> geometries = new ArrayList<Geometry>();
while (jp.getCurrentToken() != JsonToken.END_ARRAY) {
geometries.add(parseGeometry(jp));
}
jp.nextToken();//END_OBJECT } geometry
return GF.createGeometryCollection(geometries.toArray(new Geometry[geometries.size()]));
} else {
throw new SQLException("Malformed GeoJSON file. Expected 'geometries', found '" + coordinatesField + "'");
}
}
/**
* Parses a sequence of coordinates array expressed as
*
* [ [100.0, 0.0], [101.0, 1.0] ]
*
* @param jp
* @throws IOException
* @throws SQLException
* @return Coordinate[]
*/
private Coordinate[] parseCoordinates(JsonParser jp) throws IOException {
jp.nextToken(); // START_ARRAY [ to parse the each positions
ArrayList<Coordinate> coords = new ArrayList<Coordinate>();
while (jp.getCurrentToken() != JsonToken.END_ARRAY) {
coords.add(parseCoordinate(jp));
}
return coords.toArray(new Coordinate[coords.size()]);
}
/**
* Parses a GeoJSON coordinate array and returns a JTS coordinate. The first
* token corresponds to the first X value. The last token correponds to the
* end of the coordinate array "]".
*
* Parsed syntax:
*
* 100.0, 0.0]
*
* @param jp
* @throws IOException
* @return Coordinate
*/
private Coordinate parseCoordinate(JsonParser jp) throws IOException {
jp.nextToken();
double x = jp.getDoubleValue();// VALUE_NUMBER_FLOAT
jp.nextToken(); // second value
double y = jp.getDoubleValue();
Coordinate coord;
//We look for a z value
jp.nextToken();
if (jp.getCurrentToken() == JsonToken.END_ARRAY) {
coord = new Coordinate(x, y);
} else {
double z = jp.getDoubleValue();
jp.nextToken(); // exit array
coord = new Coordinate(x, y, z);
}
jp.nextToken();
return coord;
}
}