import org.locationtech.jts.geom.Coordinate;import org.locationtech.jts.geom.Polygon;import org.locationtech.jts.io.ParseException;import java.util.*;import java.util.stream.Collectors;/** * <p>Title : PolygonNodeTriangle </p> * <p>Description : 多边形自身节点组成三角形</p> * @author huifer * @date 2018/10/15 */public class PolygonNodeTriangle { private int NUM = 3; private Set result_p = new HashSet(); public static void main(String[] args) { //0 double[] point1 = new double[]{0, 0}; //1 double[] point2 = new double[]{10, 0}; //2 double[] point3 = new double[]{20, 0}; //3 double[] point4 = new double[]{10, 10}; List<double[]> allPoint = new ArrayList(); allPoint.add(point1); allPoint.add(point3); allPoint.add(point4); PolygonNodeTriangle polygonCenterPoint = new PolygonNodeTriangle(); // 外围 Polygon waiwei = polygonCenterPoint.waiwei(point1, point3, point4); // 节点三角形 List<Polygon> sanjiaoxing = polygonCenterPoint.triangleMothed(allPoint); // 外围内所有三角形 List<Polygon> rangeTriangle = polygonCenterPoint.getRangeTriangle(waiwei, sanjiaoxing); // 重心xy double[] gravityCenterXY = polygonCenterPoint.getGravityCenterXY(rangeTriangle); System.out.println(rangeTriangle.size()); System.out.println("================================================"); double[] doubles = polygonCenterPoint. polygonGravityPoint("POLYGON((0 0, 20 0, 10 10, 0 0))"); } /*** * polygon wkt 计算重心 * @param wkt * @return */ private double[] polygonGravityPoint(String wkt) { if (!wkt.startsWith("POLYGON")) { return null; } Operation operation = new Operation(); // 外围数据转 list<double[]> Polygon waiwei = null; try { waiwei = operation.createPolygonByWKT(wkt); } catch (ParseException e) { e.printStackTrace(); } Coordinate[] coordinates = waiwei.getCoordinates(); List<double[]> allP = new ArrayList<>(); Arrays.stream(coordinates).forEach( s -> { double nowX = s.x; double nowY = s.y; allP.add(new double[]{nowX, nowY}); } ); List<Polygon> polygons = triangleMothed(allP); List<Polygon> rangeTriangle1 = getRangeTriangle(waiwei, polygons); double area = waiwei.getArea(); double[] gravityCenterXY1 = getGravityCenterXY(rangeTriangle1); return gravityCenterXY1; } /*** * 重心值 * @param rangeTriangle * @return [x, y] */ private double[] getGravityCenterXY(List<Polygon> rangeTriangle) { double xArea = 0.0; double yArea = 0.0; double aArea = 0.0; for (Polygon triangle : rangeTriangle) { Coordinate[] coordinates = triangle.getCoordinates(); double area = triangle.getArea(); double[] oneGR = triangleCenterOfGravity(coordinates[0], coordinates[1], coordinates[2]); xArea += oneGR[0] * area; yArea += oneGR[1] * area; aArea += area; } System.out.println("重心X " + xArea / aArea); System.out.println("重心Y " + yArea / aArea); return new double[]{xArea / aArea, yArea / aArea}; } /*** * 范围内三角形 * @param waiwei * @param sanjiaoxing * @return */ private List<Polygon> getRangeTriangle(Polygon waiwei, List<Polygon> sanjiaoxing) { List<Polygon> triangle = new ArrayList<>(); // 判断三角形是否在面内 for (int i = 0; i < sanjiaoxing.size(); i++) { Polygon polygon = sanjiaoxing.get(i); boolean within = polygon.within(waiwei); if (within) { triangle.add(polygon); } } return triangle; } /*** * 三角形重心计算 * @param a * @param b * @param c * @return */ private double[] triangleCenterOfGravity(Coordinate a, Coordinate b, Coordinate c) { double gravityX = (a.x + b.x + c.x) / 3; double gravityY = (a.y + b.y + c.y) / 3; double[] result = new double[]{gravityX, gravityY}; return result; } /*** * 测试用外包图形 * @return */ private Polygon waiwei(double[] point1, double[] point3, double[] point4) { List<double[]> ceshimian = new ArrayList(); ceshimian.add(point1);// ceshimian.add(point2);// ceshimian.add(point7); ceshimian.add(point4);// ceshimian.add(point6);// ceshimian.add(point5); ceshimian.add(point3); String polygonForList = createPolygonForList(ceshimian); Operation op = new Operation(); Polygon polygonByWKT = null; try { polygonByWKT = op.createPolygonByWKT(polygonForList); return polygonByWKT; } catch (ParseException e) { e.printStackTrace(); } return null; } /*** * 生成所有三角形 * @param allPoint * @return */ private List<Polygon> triangleMothed(List<double[]> allPoint) { // 索引 -> 点坐标 Map<String, double[]> indexOfPoint = new HashMap(); for (int i = 0; i < allPoint.size(); i++) { indexOfPoint.put(String.valueOf(i), allPoint.get(i)); } // 排序结果 sort((List) indexOfPoint.keySet().stream().collect(Collectors.toList()), new HashSet()); // 删除元素相同后的集合 // 所有三角形 List<Polygon> allTriangle = new ArrayList(); for (Object oneDataObj : result_p) { //这一行数据 Set oneDataList = (Set) oneDataObj; // 这一行数据的三角形数据 List<double[]> trianglePoint = new ArrayList(); oneDataList.forEach( s -> trianglePoint.add(indexOfPoint.get(s) )); Polygon triangle = createTriangle(trianglePoint); if (triangle != null) { allTriangle.add(triangle); } } // 所有三角形结束 return allTriangle; } /*** * 从点坐标集合中创建一个面 * @param points * @return */ private static String createPolygonForList(List<double[]> points) { String end = "))"; String res = "POLYGON(("; Operation op = new Operation(); for (double[] point : points) { String x = Double.toString(point[0]); String y = Double.toString(point[1]); res += x + " " + y + ", "; } res += Double.toString(points.get(0)[0]) + " " + Double.toString(points.get(0)[1]); res += end; try { op.createPolygonByWKT(res); } catch (ParseException e) { e.printStackTrace(); } return res; } /*** * 创建三角形 * @param trianglePoint * @return polygon */ private static Polygon createTriangle(List<double[]> trianglePoint) { Operation op = new Operation(); String triangleWkt; boolean isTri = isTriangle(trianglePoint); if (isTri) { triangleWkt = "POLYGON((" + trianglePoint.get(0)[0] + " " + trianglePoint.get(0)[1] + ", " + trianglePoint.get(1)[0] + " " + trianglePoint.get(1)[1] + ", " + trianglePoint.get(2)[0] + " " + trianglePoint.get(2)[1] + ", " + trianglePoint.get(0)[0] + " " + trianglePoint.get(0)[1] + "))"; try { Polygon polygonByWKT = op.createPolygonByWKT(triangleWkt); return polygonByWKT;// return triangleWkt; } catch (ParseException e) { e.printStackTrace(); } } return null; } /*** * 判断三角形 * @param trianglePoint * @return */ private static boolean isTriangle(List<double[]> trianglePoint) { double[] doubles = trianglePoint.get(0); double[] doubles1 = trianglePoint.get(1); double[] doubles2 = trianglePoint.get(2); double len = Math.sqrt(Math.pow(doubles[0] - doubles1[0], 2) + Math.pow(doubles[1] - doubles1[1], 2)); double len1 = Math.sqrt(Math.pow(doubles[0] - doubles2[0], 2) + Math.pow(doubles[1] - doubles2[1], 2)); double len2 = Math.sqrt(Math.pow(doubles1[0] - doubles2[0], 2) + Math.pow(doubles1[1] - doubles2[1], 2)); if ((len + len1 > len2) && (len + len2 > len1) && (len1 + len2 > len)) { return true; } return false; } /*** * 不重复排列 (元素不相同) * @param datas * @param target */ private void sort(List datas, Set target) { if (target.size() == this.NUM) { this.result_p.add(target); return; } for (int i = 0; i < datas.size(); i++) { List newDatas = new ArrayList(datas); Set newTarget = new HashSet(target); newTarget.add(newDatas.get(i)); newDatas.remove(i); sort(newDatas, newTarget); } }} 
