简介
- 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
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表示Geometry对象
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Geometry类型介绍见另一篇文章:WKT WKB和GeoJSON
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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);}} }
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Geometry之间的关系
- 支持的空间操作包括
相等(Equals): | 几何形状拓扑上相等。 |
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脱节(Disjoint): | 几何形状没有共有的点。 |
相交(Intersects): | 几何形状至少有一个共有点(区别于脱节) |
接触(Touches): | 几何形状有至少一个公共的边界点,但是没有内部点。 |
交叉(Crosses): | 几何形状共享一些但不是所有的内部点。 |
内含(Within): | 几何形状A的线都在几何形状B内部。 |
包含(Contains): | 几何形状B的线都在几何形状A内部(区别于内含) |
重叠(Overlaps): | 几何形状共享一部分但不是所有的公共点,而且相交处有他们自己相同的区域。 |
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**/
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))"));}}