月度归档： 2017 年 11 月

Compute GPS distance

yuiwongGIS

Compute GPS distance

compute two { latitude, longitude, altitude } distance

#
– ellipsoidal distance
– spherical distance
– some online tools

ellipsoidal distance

  • 1 both latitude, longitude, altitude to ECEF xyz
    (WGS84, ENU / NED .. also ok)
  • 2 compute two 3D points distance
  • see one implementation in c++

spherical distance

  • NOTE { latitude, longitude } only and DEPRECATED

use haversine formula

Haversine
formula: a = sin²(Δφ/2) + cos φ1 ⋅ cos φ2 ⋅ sin²(Δλ/2)
c = 2 ⋅ atan2( √a, √(1−a) )
d = R ⋅ c
where φ is latitude, λ is longitude, R is earth’s radius
(mean radius = 6,371km);
note that angles need to be in radians to pass to trig functions!

// DEPRECATED please use ellipsoidalDistance or lineDistance
double Wgs84::haversineDistance(
    double const latitude,
    double const longitude,
    double const er) const
{
    double const latitude1R = DegreeToRadian(this->llh(0));
    double const longitude1R = DegreeToRadian(this->llh(1));
    double const latitude2R = DegreeToRadian(latitude);
    double const longitude2R = DegreeToRadian(longitude);
    double const deltaLatitude = latitude2R - latitude1R;// in radians
    double const deltaLongitude = longitude2R - longitude1R;// in radians
    double const a = Square(::sin(deltaLatitude / 2))
        + (::cos(latitude1R) * ::cos(latitude2R) * Square(
            ::sin(deltaLongitude / 2)));
    double const c = 2 * ::atan2(::sqrt(a), ::sqrt(1 - a));
    return er * c;
}

some online tools

see also