PHP calculation Baidu Map Two GPS coordinates distance between the method, GPS coordinates _php tutorial

PHP calculate Baidu Map Two GPS coordinates distance between the method, GPS coordinates

In this paper, we describe the method of calculating the distance between two GPS coordinates of the Baidu map in PHP. Share to everyone for your reference.

The implementation method is as follows:

Copy CodeThe code is as follows:/**
* Calculate the distance between two coordinates (m)
* @param float $fP 1Lat starting point (latitude)
* @param float $fP 1Lon starting point (longitude)
* @param float $fP 2Lat end point (latitude)
* @param float $fP 2Lon end point (longitude)
* @return int
*/
function Distancebetween ($fP 1Lat, $fP 1Lon, $fP 2Lat, $fP 2Lon) {
$fEARTH _radius = 6378137;
Angle converted to radians
$fRadLon 1 = Deg2rad ($fP 1Lon);
$fRadLon 2 = Deg2rad ($fP 2Lon);
$fRadLat 1 = Deg2rad ($fP 1Lat);
$fRadLat 2 = Deg2rad ($fP 2Lat);
Calculate the difference between latitude and longitude
$fD 1 = ABS ($fRadLat 1-$fRadLat 2);
$fD 2 = ABS ($fRadLon 1-$fRadLon 2);
Distance calculation
$fP = Pow (sin ($fD 1/2), 2) +
cos ($fRadLat 1) * cos ($fRadLat 2) * POW (sin ($fD 2/2), 2);
Return Intval ($fEARTH _radius * 2 * ASIN (SQRT ($fP)) + 0.5);
}
/**
* Baidu coordinate system converted into standard GPS seating system
* @param float $lnglat coordinates (e.g.: 106.426, 29.553404)
* @return The standard GPS value after string conversion:
*/
function bd09lltowgs84 ($fLng, $fLat) {//longitude, Latitude
$lnglat = Explode (', ', $lnglat);
List ($x, $y) = $lnglat;
$Baidu _server = "http://api.map.baidu.com/ag/coord/convert?from=0&to=4&x={$x}&y={$y}";
$result = @file_get_contents ($Baidu _server);
$json = Json_decode ($result);
if ($json->error = = 0) {
$BX = Base64_decode ($json->x);
$by = Base64_decode ($json->y);
$GPS _x = 2 * $x-$BX;
$GPS _y = 2 * $y-$by;
return $GPS _x ', '. $GPS _y;//Longitude, latitude
}else
return $lnglat;
}

I hope this article is helpful to everyone's PHP programming.

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