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

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..
}