JTS基本概念和使用

时间:2023-09-15 22:43:13
JTS基本概念和使用

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
    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);
      }
      }
      }