如何在两对纬度经度之间以几米为单位获得距离

Question

I would like to calculate distance between 2 points of latitude and longitude in PHP (NOT IN ANDROID)**i have read about **Haversine Formula and Spherical Law of Cosines for calculate distance between two points but my main motive is get best location difference between 2 points in Meters.

For Example Two devices place at next to each other and that android devices is sending location to server,So we need to take that location of each device and calculate minimum distance between these 2 device in meter.Result from Server after calculation should be like in 2-3 meters when device is placed next to each others

So what are the possible ways to calculate minimum distance between two device in meters when device next to each other on server side

Note : I need to calculate distance which i got in kms or miles which is big difference when device is next to each other. Haversine Formula and Spherical Law of Cosines is i found best way to calculate but i need to do more in these formulas to get minimum difference between 2 device.Not on Android Device. This question is not related to This Question

Answer 1

I have used the Haversine formula in PHP to calculate distance in kms between two geocoordinates:

// Haversine formula
function geoDistance($lon1, $lat1, $lon2, $lat2) {
    $R = 6371; // Radius of the earth in km
    $dLat = deg2rad($lat2 - $lat1);
    $dLon = deg2rad($lon2 - $lon1);
    $a = sin($dLat/2) * sin($dLat/2) + cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * sin($dLon/2) * sin($dLon/2);
    $c = 2 * atan2(sqrt($a), sqrt(1-$a));
    $d = $R * $c; // Distance in km

    return $d;
}

I guess, having enough precision in lon and lat would yield a result that multiplied by 1,000 migth be useful as a measure of distance in meters, right?

According to https://gis.stackexchange.com/questions/8650/measuring-accuracy-of-latitude-and-longitude the fifth decimal place is worth up to 1.1 m: it distinguish trees from each other.