JTS Geometry

JTS Geometry关系判断和分析

• JTS Geometry关系判断和分析
• 1.关系判断
• 1.1实例
• 2.关系分析
• 2.1实例
• JTS(Geometry)

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)

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);
		}
	}
}