Based on the latitude and longitude calculation distance formula, Baidu coordinates converted to GPS coordinates (PHP version)

Calculate the distance from the latitude and longitude of the formula, Baidu coordinates converted to GPS coordinates (PHP version)

 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 $lnglat;} /**********************************************/function Fn_rad ($d) {return $d * PI ()/180.0;} 2-point algorithm function p2pdistance ($latlng 1, $latlng 2) {//latitude 1, Longitude 1 ~ Latitude 2, Longitude 2$latlng1 = explode (', ', $latlng 1); $LATLNG 2 = Explode (', ', $latlng 2); list ($lat 1, $lng 1) = $latlng 1;list ($lat 2, $lng 2) = $latlng 2; $EARTH _radius = 6378.137; $radLat 1 = Fn_rad ($    LAT1); $radLat 2 = Fn_rad ($lat 2); $a = $radLat 1-$radLat 2; $b = Fn_rad ($lng 1)-Fn_rad ($lng 2); $s = 2 * ASIN (sqrt (Pow (sin ($a/2), 2) + cos ($radLat 1) *cos ($radLat 2) *pow (sin ($b/2), 2)); $s = $s * $EARTH _radius; $s = round ($s * 10000)/10000;return Number_format ($s, 2);} Echo ' Baidu coordinates: ', $lnglat, '

', ' converted GPS Coordinates: ', Frombaidutogpsxy ($lnglat), '

'; Echo ' before conversion distance: ', p2pdistance (' 31.224286666667,121.420675 ', ' 31.224665,121.437518 '), '
'; Echo ' converted distance: ', p2pdistance (' 31.224286666667,121.420675 ', ' 31.220157068379,121.42647022694 ');? >

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