JTS Geometry关系判断和分析
JTS Geometry关系判断和分析
1.关系判断
Geometry之间的关系有如下几种：
| 关系 | 说明 |
|---|---|
| 相等（Equals） | 几何形状拓扑上相等 |
| 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的内部（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 |
1.1实例
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))"));
}
}
2.关系分析
关系分析有如下几种
| 关系 | 说明 |
|---|---|
| 缓冲区分析（Buffer） | 包含所有的点在一个指定距离内的多边形和多多边形 |
| 凸壳分析（ConvexHull） | 包含几何形体的所有点的最小凸壳多边形（外包多边形） |
| 交叉分析（Intersection） | A∩B 交叉操作就是多边形AB中所有共同点的集合 |
| 联合分析（Union） | AUB AB的联合操作就是AB所有点的集合 |
| 差异分析（Difference） | (A-A∩B) AB形状的差异分析就是A里有B里没有的所有点的集合 |
| 对称差异分析（SymDifference） | (AUB-A∩B) AB形状的对称差异分析就是位于A中或者B中但不同时在AB中的所有点的集合 |
2.1实例
package com.alibaba.autonavi;
import java.util.ArrayList;
import java.util.List;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.LineString;
/**
* gemotry之间的关系分析
*
* @author xingxing.dxx
*/
public class Operation {
private GeometryFactory geometryFactory = new GeometryFactory();
/**
* create a Point
*
* @param x
* @param y
* @return
*/
public Coordinate point(double x, double y) {
return new Coordinate(x, y);
}
/**
* create a line
*
* @return
*/
public LineString createLine(List<Coordinate> points) {
Coordinate[] coords = (Coordinate[]) points.toArray(new Coordinate[points.size()]);
LineString line = geometryFactory.createLineString(coords);
return line;
}
/**
* 返回a指定距离内的多边形和多多边形
*
* @param a
* @param distance
* @return
*/
public Geometry bufferGeo(Geometry a, double distance) {
return a.buffer(distance);
}
/**
* 返回(A)与(B)中距离最近的两个点的距离
*
* @param a
* @param b
* @return
*/
public double distanceGeo(Geometry a, Geometry b) {
return a.distance(b);
}
/**
* 两个几何对象的交集
*
* @param a
* @param b
* @return
*/
public Geometry intersectionGeo(Geometry a, Geometry b) {
return a.intersection(b);
}
/**
* 几何对象合并
*
* @param a
* @param b
* @return
*/
public Geometry unionGeo(Geometry a, Geometry b) {
return a.union(b);
}
/**
* 在A几何对象中有的，但是B几何对象中没有
*
* @param a
* @param b
* @return
*/
public Geometry differenceGeo(Geometry a, Geometry b) {
return a.difference(b);
}
public static void main(String[] args) {
Operation op = new Operation();
//创建一条线
List<Coordinate> points1 = new ArrayList<Coordinate>();
points1.add(op.point(0, 0));
points1.add(op.point(1, 3));
points1.add(op.point(2, 3));
LineString line1 = op.createLine(points1);
//创建第二条线
List<Coordinate> points2 = new ArrayList<Coordinate>();
points2.add(op.point(3, 0));
points2.add(op.point(3, 3));
points2.add(op.point(5, 6));
LineString line2 = op.createLine(points2);
System.out.println(op.distanceGeo(line1, line2));//out 1.0
System.out.println(op.intersectionGeo(line1, line2));//out GEOMETRYCOLLECTION EMPTY
System.out.println(op.unionGeo(line1, line2)); //out MULTILINESTRING ((0 0, 1 3, 2 3), (3 0, 3 3, 5 6))
System.out.println(op.differenceGeo(line1, line2));//out LINESTRING (0 0, 1 3, 2 3)
}
}
JTS(Geometry)
package com.mapbar.geo.jts;
import org.geotools.geometry.jts.JTSFactoryFinder;
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;
/**
* Class GeometryDemo.java
* Description Geometry 几何实体的创建，读取操作
* Company mapbar
* author Chenll E-mail: Chenll@mapbar.com
* Version 1.0
* Date 2012-2-17 上午11:08:50
*/
public class GeometryDemo {
private GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory( null );
/**
* 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);
}
}
}