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);        }    }}

       

2. Geometry之间的关系
1. 支持的空间操作包括

package com.alibaba.autonavi;import com.vividsolutions.jts.geom.*;import com.vividsolutions.jts.io.ParseException;import com.vividsolutions.jts.io.WKTReader;/** * gemotry之间的关系 * @author xingxing.dxx * */public class GeometryRelated {    private GeometryFactory geometryFactory = new GeometryFactory();        /**     *  两个几何对象是否是重叠的     * @return     * @throws ParseException     */    public boolean equalsGeo() throws ParseException{        WKTReader reader = new WKTReader( geometryFactory );        LineString geometry1 = (LineString) reader.read("LINESTRING(0 0, 2 0, 5 0)");        LineString geometry2 = (LineString) reader.read("LINESTRING(5 0, 0 0)");        return geometry1.equals(geometry2);//true    }        /**     * 几何对象没有交点(相邻)     * @return     * @throws ParseException     */    public boolean disjointGeo() throws ParseException{        WKTReader reader = new WKTReader( geometryFactory );        LineString geometry1 = (LineString) reader.read("LINESTRING(0 0, 2 0, 5 0)");        LineString geometry2 = (LineString) reader.read("LINESTRING(0 1, 0 2)");        return geometry1.disjoint(geometry2);    }        /**     * 至少一个公共点(相交)     * @return     * @throws ParseException     */    public boolean intersectsGeo() throws ParseException{        WKTReader reader = new WKTReader( geometryFactory );        LineString geometry1 = (LineString) reader.read("LINESTRING(0 0, 2 0, 5 0)");        LineString geometry2 = (LineString) reader.read("LINESTRING(0 0, 0 2)");        Geometry interPoint = geometry1.intersection(geometry2);//相交点        System.out.println(interPoint.toText());//输出 POINT (0 0)        return geometry1.intersects(geometry2);    }    /**     * 判断以x,y为坐标的点point(x,y)是否在geometry表示的Polygon中     * @param x     * @param y     * @param geometry wkt格式     * @return     */    public boolean withinGeo(double x,double y,String geometry) throws ParseException {        Coordinate coord = new Coordinate(x,y);        Point point = geometryFactory.createPoint( coord );        WKTReader reader = new WKTReader( geometryFactory );        Polygon polygon = (Polygon) reader.read(geometry);        return point.within(polygon);    }    /**     * @param args     * @throws ParseException      */    public static void main(String[] args) throws ParseException {        GeometryRelated gr = new GeometryRelated();        System.out.println(gr.equalsGeo());        System.out.println(gr.disjointGeo());        System.out.println(gr.intersectsGeo());        System.out.println(gr.withinGeo(5,5,"POLYGON((0 0, 10 0, 10 10, 0 10,0 0))"));    }}