extract GPS data

[ggalan]

i am trying to get lat, long numbers from images that have geo tags using
exif_read_data();
i found this code and people say that it works well but its producing errors for me

Undefined index: GPSLongitude
Undefined index: GPSLongitudeRef
Undefined index: GPSLatitude
Undefined index: GPSLatitudeRef

function getGps($exifCoord, $hemi) {

    $degrees = count($exifCoord) > 0 ? gps2Num($exifCoord[0]) : 0;
    $minutes = count($exifCoord) > 1 ? gps2Num($exifCoord[1]) : 0;
    $seconds = count($exifCoord) > 2 ? gps2Num($exifCoord[2]) : 0;

    $flip = ($hemi == 'W' or $hemi == 'S') ? -1 : 1;

    return $flip * ($degrees + $minutes / 60 + $seconds / 3600);

}

function gps2Num($coordPart) {

    $parts = explode('/', $coordPart);

    if (count($parts) <= 0)
        return 0;

    if (count($parts) == 1)
        return $parts[0];

    return floatval($parts[0]) / floatval($parts[1]);
}



$filename = "IMG_1406.jpeg";
$exif = exif_read_data($filename, 'IDF0');
$lon = getGps($exif["GPSLongitude"], $exif['GPSLongitudeRef']);
$lat = getGps($exif["GPSLatitude"], $exif['GPSLatitudeRef']);
var_dump($lat, $lon);

also, i made sure in my php.ini
extension=php_mbstring.dll
extension=php_exif.dll

and not:

extension=php_exif.dll
extension=php_mbstring.dll

any suggestions on how to get this to work please
thank you


re: just found out that it was the jpg
images with geo tag will output lat/long coordinates correctly