简介

1. JTS是加拿大的 Vivid Solutions公司做的一套开放源码的 Java API。它提供了一套空间数据操作的核心算法。为在兼容OGC标准的空间对象模型中进行基础的几何操作提供2D空间谓词API。

操作

1. 表示Geometry对象
   1. Geometry类型介绍见另一篇文章：WKT WKB和GeoJSON

   2. package com.alibaba.autonavi;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.Point;
      import com.vividsolutions.jts.geom.Polygon;
      import com.vividsolutions.jts.geom.MultiPolygon;
      import com.vividsolutions.jts.geom.MultiLineString;
      import com.vividsolutions.jts.geom.MultiPoint;
      import com.vividsolutions.jts.io.ParseException;
      import com.vividsolutions.jts.io.WKTReader;public class GeometryDemo {private GeometryFactory geometryFactory = new GeometryFactory();/*** create a point* @return*/public Point createPoint(){Coordinate coord = new Coordinate(109.013388, 32.715519);Point point = geometryFactory.createPoint( coord );return point;}/*** create a point by WKT* @return* @throws ParseException */public Point createPointByWKT() throws ParseException{WKTReader reader = new WKTReader( geometryFactory );Point point = (Point) reader.read("POINT (109.013388 32.715519)");return point;}/*** create multiPoint by wkt* @return*/public MultiPoint createMulPointByWKT()throws ParseException{WKTReader reader = new WKTReader( geometryFactory );MultiPoint mpoint = (MultiPoint) reader.read("MULTIPOINT(109.013388 32.715519,119.32488 31.435678)");return mpoint;}/*** * create a line* @return*/public LineString createLine(){Coordinate[] coords  = new Coordinate[] {new Coordinate(2, 2), new Coordinate(2, 2)};LineString line = geometryFactory.createLineString(coords);return line;}/*** create a line by WKT* @return* @throws ParseException*/public LineString createLineByWKT() throws ParseException{WKTReader reader = new WKTReader( geometryFactory );LineString line = (LineString) reader.read("LINESTRING(0 0, 2 0)");return line;}/*** create multiLine * @return*/public MultiLineString createMLine(){Coordinate[] coords1  = new Coordinate[] {new Coordinate(2, 2), new Coordinate(2, 2)};LineString line1 = geometryFactory.createLineString(coords1);Coordinate[] coords2  = new Coordinate[] {new Coordinate(2, 2), new Coordinate(2, 2)};LineString line2 = geometryFactory.createLineString(coords2);LineString[] lineStrings = new LineString[2];lineStrings[0]= line1;lineStrings[1] = line2;MultiLineString ms = geometryFactory.createMultiLineString(lineStrings);return ms;}/*** create multiLine by WKT* @return* @throws ParseException*/public MultiLineString createMLineByWKT()throws ParseException{WKTReader reader = new WKTReader( geometryFactory );MultiLineString line = (MultiLineString) reader.read("MULTILINESTRING((0 0, 2 0),(1 1,2 2))");return line;}/*** create a polygon(多边形) by WKT* @return* @throws ParseException*/public Polygon createPolygonByWKT() throws ParseException{WKTReader reader = new WKTReader( geometryFactory );Polygon polygon = (Polygon) reader.read("POLYGON((20 10, 30 0, 40 10, 30 20, 20 10))");return polygon;}/*** create multi polygon by wkt* @return* @throws ParseException*/public MultiPolygon createMulPolygonByWKT() throws ParseException{WKTReader reader = new WKTReader( geometryFactory );MultiPolygon mpolygon = (MultiPolygon) reader.read("MULTIPOLYGON(((40 10, 30 0, 40 10, 30 20, 40 10),(30 10, 30 0, 40 10, 30 20, 30 10)))");return mpolygon;}/*** create GeometryCollection  contain point or multiPoint or line or multiLine or polygon or multiPolygon* @return* @throws ParseException*/public GeometryCollection createGeoCollect() throws ParseException{LineString line = createLine();Polygon poly =  createPolygonByWKT();Geometry g1 = geometryFactory.createGeometry(line);Geometry g2 = geometryFactory.createGeometry(poly);Geometry[] garray = new Geometry[]{g1,g2};GeometryCollection gc = geometryFactory.createGeometryCollection(garray);return gc;}/*** create a Circle  创建一个圆，圆心(x,y) 半径RADIUS* @param x* @param y* @param RADIUS* @return*/public Polygon createCircle(double x, double y, final double RADIUS){final int SIDES = 32;//圆上面的点个数Coordinate coords[] = new Coordinate[SIDES+1];for( int i = 0; i < SIDES; i++){double angle = ((double) i / (double) SIDES) * Math.PI * 2.0;double dx = Math.cos( angle ) * RADIUS;double dy = Math.sin( angle ) * RADIUS;coords[i] = new Coordinate( (double) x + dx, (double) y + dy );}coords[SIDES] = coords[0];LinearRing ring = geometryFactory.createLinearRing( coords );Polygon polygon = geometryFactory.createPolygon( ring, null );return polygon;}/*** @param args* @throws ParseException */public static void main(String[] args) throws ParseException {GeometryDemo gt = new GeometryDemo();Polygon p = gt.createCircle(0, 1, 2);//圆上所有的坐标(32个)Coordinate coords[] = p.getCoordinates();for(Coordinate coord:coords){System.out.println(coord.x+","+coord.y);}}
      }