private function computeGps($exifCoord, $hemi)
{
$degrees = count($exifCoord) > 0 ? Image::computeGps2Num($exifCoord[0]) : 0;
$minutes = count($exifCoord) > 1 ? Image::computeGps2Num($exifCoord[1]) : 0;
$seconds = count($exifCoord) > 2 ? Image::computeGps2Num($exifCoord[2]) : 0;
$flip = ($hemi == 'W' or $hemi == 'S') ? -1 : 1;
return $flip * ($degrees + $minutes / 60 + $seconds / 3600);
}