通过坐标计算GPS点之间的距离

Question

I'm having some trouble computing the distance between two GPS points by their coordinates.

point a
x = 7,2562
y = 47,7434599999999

point b 
x = 7,21978
y = 47,73836

I used the Haversine formula as described here . The result I get is 4.09 km.

However, locating those points on a map using a tool like this , I can measure a distance of 2.8 km

Several other formulas I tried also return a result around 4 km.

Any ideas what I would be missing ?

Answer 1

I think is because u are using the function in miles, in Kms you can use something like that:

    public static function distance(
        array $from,
        array $to
    ) {
        if (empty($from['lat']) || empty($to['lat'])) {
            return $to['distance'];
        }

        $latitude1  = (float) $from['lat'];
        $latitude2  = (float) $to['lat'];
        $longitude1 = (float) $from['lng'];
        $longitude2 = (float) $to['lng'];

        $theta = $longitude1 - $longitude2;
        $distance = (sin(deg2rad($latitude1)) * sin(deg2rad($latitude2)))
            + (cos(deg2rad($latitude1)) * cos(deg2rad($latitude2)) * cos(deg2rad($theta)))
        ;
        $distance = acos($distance);
        $distance = rad2deg($distance);
        $distance = $distance * 60 * 1.1515;
        $distance = (is_nan($distance)) ? 0 : $distance * 1.609344;

        return  $distance;
    }

Answer 2

As pointed out by Roland Starke in the comments, the problem was the order of the coordinates. (7, 47 not 47, 7)