Calculating the distance between 2 latitudes and longitudes that are saved in a text file?

Question

I\'ve looked around and still couldn\'t find anything to help me really! I\'ve written a program to calculate the distance between 2 cities using their Latitudes and Longitu

Answer 1

Using boost.geometry

typedef boost::geometry::model::point<
    double, 2, boost::geometry::cs::spherical_equatorial<boost::geometry::degree>
> spherical_point;

spherical_point p(lon1_degree, lat1_degree);
spherical_point q(lon2_degree, lat2_degree);
double dist = boost::geometry::distance(p, q);
double const earth_radius = 6371.0; // Km
double dist_km = dist*earth_radius;

Answer 2

As it is said, Haversine formula is your answer:

#include <math.h>
#include <cmath> 
#define earthRadiusKm 6371.0

// This function converts decimal degrees to radians
double deg2rad(double deg) {
  return (deg * M_PI / 180);
}

//  This function converts radians to decimal degrees
double rad2deg(double rad) {
  return (rad * 180 / M_PI);
}

/**
 * Returns the distance between two points on the Earth.
 * Direct translation from http://en.wikipedia.org/wiki/Haversine_formula
 * @param lat1d Latitude of the first point in degrees
 * @param lon1d Longitude of the first point in degrees
 * @param lat2d Latitude of the second point in degrees
 * @param lon2d Longitude of the second point in degrees
 * @return The distance between the two points in kilometers
 */
double distanceEarth(double lat1d, double lon1d, double lat2d, double lon2d) {
  double lat1r, lon1r, lat2r, lon2r, u, v;
  lat1r = deg2rad(lat1d);
  lon1r = deg2rad(lon1d);
  lat2r = deg2rad(lat2d);
  lon2r = deg2rad(lon2d);
  u = sin((lat2r - lat1r)/2);
  v = sin((lon2r - lon1r)/2);
  return 2.0 * earthRadiusKm * asin(sqrt(u * u + cos(lat1r) * cos(lat2r) * v * v));
}

Answer 3

This is the method that I would use for finding the distance

Or this, not concidering the "bend" of the Earth

Answer 4

for people who need in swift:

  // Haversine formula:

    func deg2rad(_ deg: Double) ->Double {
        return deg * Double.pi  / 180.0
    }

    func distanceEarth(lat1d: Double, lon1d: Double, lat2d: Double, lon2d: Double) ->Double {
    let  earthRadiusKm = 6371.0

    let lat1r = deg2rad(lat1d);
    let lon1r = deg2rad(lon1d);
    let lat2r = deg2rad(lat2d);
    let lon2r = deg2rad(lon2d);
    let u = sin((lat2r - lat1r)/2);
    let v = sin((lon2r - lon1r)/2);
    return 2.0 * earthRadiusKm * asin(sqrt(u * u + cos(lat1r) * cos(lat2r) * v * v));
}

//test here.... https://andrew.hedges.name/experiments/haversine/


func doTestHaversine(){

    let km = distanceEarth(lat1d: 38.898556, lon1d: -77.037852, lat2d: 38.897147, lon2d: -77.043934)
     print(km)  // should show : 0.549 or similar..
}