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计算两个直接距离 /**
* 单位：米
*
* @param lon1
* @param lat1
* @param lon2
* @param lat2
* @return
*/
public static double getDistance(double lon1, double lat1, double lon2, double lat2) {
double radLat1 = rad(lat1);
double radLat2 = rad(lat2);
double a = radLat1 - radLat2;
double b = rad(lon1) - rad(lon2);
double c = 2 * Math.asin(Math.sqrt(
Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
c = c * 6378.137;// 6378.137赤道半径
return (Math.round(c * 10000d) / 10000d) * 1000;
}
private static double rad(double d) {
return d * Math.PI / 180.0;
}
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三角形面积 public static Double calculateArea(Loca A, Loca B, Loca C) {
Double a = getDistance(A.getLongitude(), A.getLatitude(), B.getLongitude(), B.getLatitude());
Double b = getDistance(B.getLongitude(), B.getLatitude(), C.getLongitude(), C.getLatitude());
Double c = getDistance(C.getLongitude(), C.getLatitude(), A.getLongitude(), A.getLatitude());
Double p = (a + b + c) / 2;
Double area = Math.sqrt(p * Math.abs((p - a)) * Math.abs((p - b)) * Math.abs((p - c)));
return area;
}
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多边形面积 /**
* 获取多边形面积，单位：平方米
*
* @param pointsStr
* @return
*/
public static Double getEnclArea(String pointsStr) throws Exception {
JSONArray jsonArray = JSONArray.parseArray(pointsStr);
Double Spoints = 0.0;
if (jsonArray != null && jsonArray.size() > 2) {
List<Loca> locas = new ArrayList<>();
for (int i = 0; i < jsonArray.size(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
Loca loca = new Loca();
Double latitude = jsonObject.getDouble("latitude");
Double longitude = jsonObject.getDouble("longitude");
loca.setLatitude(latitude);
loca.setLongitude(longitude);
locas.add(loca);
}
Loca lowestPoint = locas.get(0);
Integer lowestIndex = 0;
List<Loca> lastList = new ArrayList<>();
for (int i = 0; i < locas.size(); i++) {
Loca point = locas.get(i);
if (point.getLatitude() < lowestPoint.getLatitude()) {
lowestIndex = i;
lowestPoint = point;
}
}
System.out.println("lowestIndex:" + lowestIndex);
for (int i = lowestIndex; i < locas.size(); i++) {
lastList.add(locas.get(i));
}
for (int i = 0; i < lowestIndex; i++) {
lastList.add(locas.get(i));
}
for (int i = 0; i < lastList.size() - 2; i++) {
Loca A = lastList.get(0);
Loca B = lastList.get(i + 1);
Loca C = lastList.get(i + 2);
if (A.getLongitude() == B.getLongitude() && A.getLongitude() == C.getLongitude()) {
//k1 、k2不存在
continue;
} else if (A.getLongitude() == B.getLongitude()) {
//k1不存在 k2存在
Double k2 = (C.getLatitude() - A.getLatitude()) / (C.getLongitude() - A.getLongitude());
if (k2 < 0) {//凹
Spoints -= calculateArea(A, B, C);
} else {//凸
Spoints += calculateArea(A, B, C);
}
} else if (A.getLongitude() == C.getLongitude()) {
//k1存在 k2不存在
Double k1 = (B.getLatitude() - A.getLatitude()) / (B.getLongitude() - A.getLongitude());
if (k1 > 0) {//凹
Spoints -= calculateArea(A, B, C);
} else {//凸
Spoints += calculateArea(A, B, C);
}
} else {
//k1、k2都存在
Double k1 = (B.getLatitude() - A.getLatitude()) / (B.getLongitude() - A.getLongitude());
Double k2 = (C.getLatitude() - A.getLatitude()) / (C.getLongitude() - A.getLongitude());
if (k1 > 0 && k2 < 0) {//凹
Spoints -= calculateArea(A, B, C);
} else if (k1 < 0 && k2 < 0) {//同号都为负数
if (k1 < k2) {//凹
Spoints -= calculateArea(A, B, C);
} else {//凸
Spoints += calculateArea(A, B, C);
}
} else if (k1 > 0 && k2 > 0) {//同号都为正数
if (k1 < k2) {//凹
Spoints -= calculateArea(A, B, C);
} else {//凸
Spoints += calculateArea(A, B, C);
}
} else {//其余情况都为凸
Spoints += calculateArea(A, B, C);
}
}
}
}
DecimalFormat df = new DecimalFormat("#.00");
return Double.valueOf(df.format(Math.abs(Spoints)));
}
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