/**
?* 計算兩個坐標之間的距離(米)
?* @param float $fP1Lat 起點(緯度)
?* @param float $fP1Lon 起點(經度)
?* @param float $fP2Lat 終點(緯度)
?* @param float $fP2Lon 終點(經度)
?* @return int
?*/
function distanceBetween($fP1Lat, $fP1Lon, $fP2Lat, $fP2Lon){
??? $fEARTH_RADIUS = 6378137;
??? //角度換算成弧度
??? $fRadLon1 = deg2rad($fP1Lon);
??? $fRadLon2 = deg2rad($fP2Lon);
??? $fRadLat1 = deg2rad($fP1Lat);
??? $fRadLat2 = deg2rad($fP2Lat);
??? //計算經緯度的差值
??? $fD1 = abs($fRadLat1 - $fRadLat2);
??? $fD2 = abs($fRadLon1 - $fRadLon2);
??? //距離計算
??? $fP = pow(sin($fD1/2), 2) +
????????? cos($fRadLat1) * cos($fRadLat2) * pow(sin($fD2/2), 2);
??? return intval($fEARTH_RADIUS * 2 * asin(sqrt($fP)) + 0.5);
}
/**
?* 百度坐標系轉換成標準GPS坐系
?* @param float $lnglat 坐標(如:106.426, 29.553404)
?* @return string 轉換后的標準GPS值:
?*/
function BD09LLtoWGS84($fLng, $fLat){ // 經度,緯度
??? $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;//經度,緯度
??? }else
??????? return $lnglat;
}