synchronizing the location with the gps exif metadata fails

[bhlevca]

Although the pictures have the GPS information enabled automatic synchronisation (photo management page) fails with the following warning:

Warning: Invalid argument supplied for foreach() in /mnt/sda1/var/www/piwigo/plugins/exiftool_gps/main.inc.php on line 23

Several thoughts:

1. For one album automatic geotaging has worked for others did not.
2. manual geocoding with setting lat lon has worked.
3. The logitude convention the the little helper text of the page is wrong. The correct sign is negative for west and not the other way around.