c++ - 大圆距离c++

Question

我已经包含了大圆距离公式的代码(现在)。代码一直有效，直到其中一个纬度/经度附加了 S/E 作为它们各自的方向(我试图使用 S/E 作为“负方向”)。非常感谢任何帮助!

#include <iostream>
#include <math.h>
#include "lat.hpp"
#include <string>

#define PI 3.14159265


double greatCircleDistance(double lat1, double long1, char latDir1 ,
                            char longDir1, double lat2, double long2,
                            char latDir2, char longDir2)
  {
  double dLat;
  double dLong;

   latDirectionCheck(latDir1, lat1);
   latDirectionCheck(latDir2, lat2);
   longDirectionCheck(longDir1, long1);
   longDirectionCheck(longDir2, long2);

   dLat = (lat1 - lat2) ;
   dLong = (long1 - long2);

   positivify(dLat);
   positivify(dLong);
   positivify(lat1);
   positivify(lat2);

    //convert all numbers to Rad
    dLat = convertRadians(dLat);
    dLong = convertRadians(dLong);
    lat1 = convertRadians(lat1);
    lat2 = convertRadians(lat2);

    double R = 3959.9;
    double num1 = sin(dLat/2);
    double num2 = sin(dLong/2);



    double a = pow(num1,2) + cos(lat1) * cos(lat2) *
               pow(num2,2);
    double c = 2 * atan2(sqrt(a), sqrt(1-a));
    double d = R * c;
    return d;
   }

 double latDirectionCheck(char check, double convert) {
     if(check == 'S') 
      convert = -convert;
      return convert;
 }

 double longDirectionCheck(char check, double convert) {
    if(check == 'E')
       convert = -convert;
       return convert;
    }

 double positivify(double num) {
    if (num < 0) 
    num = num*(-1);
    return num;
 }

 bool compareFarDistance(double num1, double num2) {
    bool statement = false;
    if(num1 > num2)
        statement = true;
        return statement; 
 }

 bool compareCloseDistance(double num1, double num2) {
    bool statement = false;
    if(num1 < num2)
        statement = true;
        return statement;
 }
 double convertRadians(double num) {
   num = PI*(num/180);
   return num;
 }

 double convertDegrees(double num) {
    num = 180 * (num/PI);
    return num;

 }

输入:23.4356/S 46.4731/W

距离输出:4335.48

Answer 1

您不使用各种方向检查函数或 positivify 函数的返回值，它们按值获取参数。所以它们没有效果。您要么需要通过引用向它们传递参数，要么使用它们的返回值。否则，它们会计算一个值并将其返回给忽略它的代码。