JTS基本概念和使用

深碍√TFBOYSˉ_ 2023-09-30 13:44 35阅读 0赞

## 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][WKT WKB_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

<table> 
 <thead> 
  <tr> 
   <th>相等(Equals)：</th> 
   <th>几何形状拓扑上相等。</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>脱节(Disjoint)：</td> 
   <td>几何形状没有共有的点。</td> 
  </tr> 
  <tr> 
   <td>相交(Intersects)：</td> 
   <td>几何形状至少有一个共有点（区别于脱节）</td> 
  </tr> 
  <tr> 
   <td>接触(Touches)：</td> 
   <td>几何形状有至少一个公共的边界点，但是没有内部点。</td> 
  </tr> 
  <tr> 
   <td>交叉(Crosses)：</td> 
   <td>几何形状共享一些但不是所有的内部点。</td> 
  </tr> 
  <tr> 
   <td>内含(Within)：</td> 
   <td>几何形状A的线都在几何形状B内部。</td> 
  </tr> 
  <tr> 
   <td>包含(Contains)：</td> 
   <td>几何形状B的线都在几何形状A内部（区别于内含）</td> 
  </tr> 
  <tr> 
   <td>重叠(Overlaps)：</td> 
   <td>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。</td> 
  </tr> 
 </tbody> 
</table>

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))"));
        }
    
    }

[WKT WKB_GeoJSON]: http://www.cnblogs.com/duanxingxing/p/5144257.html