#39617 [Asn->Fbk]: Erroneously uses the GPS version tag to determine byte order of GPS fields

ID: 39617 Updated by: jani@php.net Reported By: me+php at drbeat dot li -Status: Assigned +Status: Feedback Bug Type: EXIF related Operating System: * PHP Version: 5.2.0 Assigned To: helly New Comment: Please try using this CVS snapshot: http://snaps.php.net/php5.2-latest.tar.gz For Windows: http://windows.php.net/snapshots/ Previous Comments: ------------------------------------------------------------------------ [2006-11-25 19:26:34] me+php at drbeat dot li Sorry, wrong link :-( The picture is at http://www.drbeat.li/test/images/testgps.jpg Additionally, a correct image is at http://www.drbeat.li/test/images/testgps2.jpg ------------------------------------------------------------------------ [2006-11-25 15:34:50] helly@php.net http://www.exif.org/Exif2-2.PDF A. Tags Relating to GPS GPSVersionID Indicates the version of GPSInfoIFD. The version is given as 2.2.0.0. This tag is mandatory when GPSInfo tag is present. Note that the GPSVersionID tag is written as a different byte than the Exif Version tag. Tag = 0 (0.H) Type = BYTE Count = 4 Default = 2.2.0.0 2.2.0.0 = Version 2.2 Other = reserved ====================================== That is your GPS IFD is corrupted. No matter what the byte order is - the version is always stored in the same order. To analyze whether t he whole data is corrupted or there is still an error in ext/exif i would need the image. ------------------------------------------------------------------------ [2006-11-24 16:16:43] me+php at drbeat dot li BTW, this image was resized in Apple's iPhoto. ------------------------------------------------------------------------ [2006-11-24 13:19:02] me+php at drbeat dot li Description: ------------ When reading GPS EXIF tags, PHP seems to use the GPS version tag to determine the byte order of the other GPS tags instead of the byte order indicator from the EXIF header. An image that shows the incorrect behavior is at http://www.drbeat.li/test/testgps.jpg . In this picture, the GPS tag version is stored as the bytes [0, 0, 2, 2] instead of as [2, 2, 0, 0]. exif_read_data() consequently returns wrong fractions for latitude, longitude and altitude. Reproduce code: --------------- if (($exif = @exif_read_data($file, 0, true)) !== false && $exif['GPS']) print_r($exif['GPS']); Expected result: ---------------- Array ( [GPSVersion] => ???? [GPSLatitudeRef] => N [GPSLatitude] => Array ( [0] => 47/1 [1] => 8/1 [2] => 96/25 ) [GPSLongitudeRef] => E [GPSLongitude] => Array ( [0] => 7/1 [1] => 13/1 [2] => 60801/1250 ) [GPSAltitudeRef] => ? [GPSAltitude] => 436/1 ) Actual result: -------------- Array ( [GPSVersion] => ???? [GPSLatitudeRef] => N [GPSLatitude] => Array ( [0] => 196608/3276800 [1] => 65536/2004877312 [2] => 57999413/-1526726656 ) [GPSLongitudeRef] => E [GPSLongitude] => Array ( [0] => 38666275/3080192 [1] => 65536/524288 [2] => 65536/6291456 ) [GPSAltitudeRef] => ? [GPSAltitude] => 1638400/458752 ) ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=39617&edit=1