【JTS】JTS空間拓撲關係的測試

在JTS中有九種拓撲關係函數，touches、covers、within、crosses、intersects、disjoint、equals、overlaps、contains、coveredBy。
對於線，環，多邊形這三種各有不同的特點，線不閉合，環是閉合的，多邊形是一種面狀。三者分別對應JTS中的LineString、LinearRing、Polygon。

JTS的jar包和開發文檔下載地址：
JTS 1.14

下面我們用JTS做個拓撲關係的測試。

代碼如下：

package test;

import java.util.ArrayList;
import java.util.List;

import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.geom.LinearRing;
import com.vividsolutions.jts.geom.impl.CoordinateArraySequence;

public class Test {
    /**
     * 實驗說明，LinearRing是線，polygon是多邊形，線內部和多邊形內部不一樣，線的子集是在線上，也是內部（within），多邊形是面
     * @param args
     */
    public static void main(String[] args) {
        Coordinate[] coor_arr1=new Coordinate[5];
//      coor_arr1[0]=new Coordinate(114.254398, 30.665175);
//      coor_arr1[1]=new Coordinate(114.254398, 30.525956);
//      coor_arr1[2]=new Coordinate(114.392427, 30.525956);
//      coor_arr1[3]=new Coordinate(114.392427, 30.665175);
//      coor_arr1[4]=new Coordinate(114.254398, 30.665175);
        coor_arr1[0]=new Coordinate(114.254398, 30.665175);
        coor_arr1[1]=new Coordinate(114.392427, 30.665175);
        coor_arr1[2]=new Coordinate(114.392427, 30.525956);
        coor_arr1[3]=new Coordinate(114.254398, 30.525956);
        coor_arr1[4]=new Coordinate(114.254398, 30.665175);
        CoordinateArraySequence seq=new CoordinateArraySequence(coor_arr1);
        LinearRing ring = new LinearRing(seq, new GeometryFactory());
        String string="114.254398 30.665175, 114.392427 30.665175";
//      String string="114.287 30.5964, 114.2877 30.5971, 114.2885 30.5979, 114.2894 30.5988, 114.2912 30.6002, 114.292 30.6009, 114.2925 30.6013, 114.2942 30.6028, 114.2949 30.6032, 114.296 30.6046, 114.2971 30.6059, 114.2975 30.6065, 114.298 30.6072, 114.2985 30.608, 114.2991 30.6089";
        String[] arr=string.split(", ");
        List<Coordinate> coors=new ArrayList<>();
        for(String temp:arr){
            String[] xy=temp.split(" ");
            Coordinate coor=new Coordinate(Double.parseDouble(xy[0]), Double.parseDouble(xy[1]));
            coors.add(coor);
        }
        Coordinate[] coor_arr=coors.toArray(new Coordinate[0]);
        LineString l_s=new GeometryFactory().createLineString(coor_arr);
//      Polygon poly=new Polygon(ring, null, new GeometryFactory());
//      System.out.println(poly.contains(l_s));
//      System.out.println(poly.touches(l_s));
//      System.out.println(poly.covers(l_s));
//      System.out.println(poly.within(l_s));
//      System.out.println(poly.crosses(l_s));
//      System.out.println(poly.intersects(l_s));
//      System.out.println(poly.equals(l_s));
//      System.out.println(poly.overlaps(l_s));
//      System.out.println(poly.coveredBy(l_s));
        System.out.println("-----------------");
        System.out.println(l_s.touches(ring));
        System.out.println(l_s.covers(ring));
        System.out.println(l_s.within(ring));
        System.out.println(l_s.crosses(ring));
        System.out.println(l_s.intersects(ring));
        System.out.println(l_s.disjoint(ring));
        System.out.println(l_s.equals(ring));
        System.out.println(l_s.overlaps(ring));
        System.out.println(l_s.contains(ring));
        System.out.println(l_s.coveredBy(ring));
        System.out.println("---------");
        System.out.println(ring.touches(l_s));
        System.out.println(ring.covers(l_s));
        System.out.println(ring.within(l_s));
        System.out.println(ring.crosses(l_s));
        System.out.println(ring.intersects(l_s));
        System.out.println(ring.disjoint(l_s));
        System.out.println(ring.equals(l_s));
        System.out.println(ring.overlaps(l_s));
        System.out.println(ring.contains(l_s));
        System.out.println(ring.coveredBy(l_s));
        System.out.println(ring.relate(l_s));
//      LINEARRING (114.254398 30.665175, 114.254398 30.525956, 114.392427 30.525956, 114.392427 30.665175, 114.254398 30.665175)
//      LINESTRING (114.3013 30.5228, 114.3026 30.5233, 114.3042 30.5246, 114.305 30.5261, 114.3058 30.5265, 114.3069 30.5266, 114.3083 30.5268, 114.3091 30.5261, 114.3104 30.525, 114.311 30.5242, 114.312 30.5234, 114.313 30.523, 114.3144 30.5226, 114.3156 30.5224, 114.3163 30.5221, 114.3168 30.522, 114.3176 30.522, 114.3181 30.5217)
    }

}

從上面的測試可以得出一個結論，就是LinearRing和Polygon是不同的。一個是線，一個是面。

假如有以下數據：
LineString類型的數據A、LinearRing類型的數據B、Polygon類型的數據C 以及 落在B上的線D（完全落在，屬於子集關係）。
其中，B和C除了一個是線，一個是面之外，邊界完全重合，A是落在B和C內部的。

那麼通過上面的代碼測試，可以知道
A.within（B）結果爲false，A.within（C）結果爲true，D.within（B）結果爲true。
也就是說，線是within面內部的，但不是within一個線組成的環內部的（即使該線空間座標是落在裏面的）。