增加多边形中心，重心点计算

basic-util/src/main/java/ink/wgink/util/point/PointUtil.java

@@ -19,6 +19,11 @@ public class PointUtil {
     private static final double RADIAN = Math.PI / 180.00D;
     private static final double HALF = 0.5D;
 
+    public static final double MIN_LAT = -90;
+    public static final double MAX_LAT = 90;
+    public static final double MIN_LNG = -180;
+    public static final double MAX_LNG = 180;
+
     /**
      * 点在多边形内
      *
@@ -301,4 +306,97 @@ public class PointUtil {
         return Math.abs(area);
     }
 
+    /**
+     * 计算中心点
+     *
+     * @param mPoints
+     * @return
+     */
+    public static Point getCenterPoint(List<Point> mPoints) {
+        double latitude = (getMinLatitude(mPoints) + getMaxLatitude(mPoints)) / 2;
+        double longitude = (getMinLongitude(mPoints) + getMaxLongitude(mPoints)) / 2;
+        return new Point(latitude, longitude);
+    }
+
+
+    /**
+     * 获取不规则多边形重心点
+     *
+     * @param mPoints
+     * @return
+     */
+    public static Point getCenterOfGravityPoint(List<Point> mPoints) {
+        double area = 0.0;//多边形面积
+        double Gx = 0.0, Gy = 0.0;// 重心的x、y
+        for (int i = 1; i <= mPoints.size(); i++) {
+            double iLat = mPoints.get(i % mPoints.size()).getX();
+            double iLng = mPoints.get(i % mPoints.size()).getY();
+            double nextLat = mPoints.get(i - 1).getX();
+            double nextLng = mPoints.get(i - 1).getY();
+            double temp = (iLat * nextLng - iLng * nextLat) / 2.0;
+            area += temp;
+            Gx += temp * (iLat + nextLat) / 3.0;
+            Gy += temp * (iLng + nextLng) / 3.0;
+        }
+        Gx = Gx / area;
+        Gy = Gy / area;
+        return new Point(Gx, Gy);
+    }
+
+    // 经度最小值
+    public static double getMinLongitude(List<Point> mPoints) {
+        double minLongitude = MAX_LNG;
+        if (mPoints.size() > 0) {
+            minLongitude = mPoints.get(0).getY();
+            for (Point latlng : mPoints) {
+                // 经度最小值
+                if (latlng.getY() < minLongitude)
+                    minLongitude = latlng.getY();
+            }
+        }
+        return minLongitude;
+    }
+
+    // 经度最大值
+    public static double getMaxLongitude(List<Point> mPoints) {
+        double maxLongitude = MIN_LNG;
+        if (mPoints.size() > 0) {
+            maxLongitude = mPoints.get(0).getY();
+            for (Point latlng : mPoints) {
+                // 经度最大值
+                if (latlng.getY() > maxLongitude)
+                    maxLongitude = latlng.getY();
+            }
+        }
+        return maxLongitude;
+    }
+
+    // 纬度最小值
+    public static double getMinLatitude(List<Point> mPoints) {
+        double minLatitude = MAX_LAT;
+        if (mPoints.size() > 0) {
+            minLatitude = mPoints.get(0).getX();
+            for (Point latlng : mPoints) {
+                // 纬度最小值
+                if (latlng.getX() < minLatitude)
+                    minLatitude = latlng.getX();
+            }
+        }
+        return minLatitude;
+    }
+
+    // 纬度最大值
+    public static double getMaxLatitude(List<Point> mPoints) {
+        double maxLatitude = MIN_LAT;
+        if (mPoints.size() > 0) {
+            maxLatitude = mPoints.get(0).getX();
+            for (Point latlng : mPoints) {
+                // 纬度最大值
+                if (latlng.getX() > maxLatitude)
+                    maxLatitude = latlng.getX();
+            }
+        }
+        return maxLatitude;
+    }
+
 }