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<?php
//================================================================================================
//================================================================================================
//================================================================================================
/*
Exifer
Extracts EXIF information from digital photos.
Copyright © 2003 Jake Olefsky
http://www.offsky.com/software/exif/index.php
jake@olefsky.com
Please see exif.php for the complete information about this software.
------------
This program is free software; you can redistribute it and/or modify it under the terms of
the GNU General Public License as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details. http://www.gnu.org/copyleft/gpl.html
*/
//================================================================================================
//================================================================================================
//================================================================================================
//=================
// Looks up the name of the tag
//====================================================================
function lookup_GPS_tag($tag) {
switch($tag) {
case "0000": $tag = "Version";break;
case "0001": $tag = "Latitude Reference";break; //north or south
case "0002": $tag = "Latitude";break; //dd mm.mm or dd mm ss
case "0003": $tag = "Longitude Reference";break; //east or west
case "0004": $tag = "Longitude";break; //dd mm.mm or dd mm ss
case "0005": $tag = "Altitude Reference";break; //sea level or below sea level
case "0006": $tag = "Altitude";break; //positive rational number
case "0007": $tag = "Time";break; //three positive rational numbers
case "0008": $tag = "Satellite";break; //text string up to 999 bytes long
case "0009": $tag = "ReceiveStatus";break; //in progress or interop
case "000a": $tag = "MeasurementMode";break; //2D or 3D
case "000b": $tag = "MeasurementPrecision";break; //positive rational number
case "000c": $tag = "SpeedUnit";break; //KPH, MPH, knots
case "000d": $tag = "ReceiverSpeed";break; //positive rational number
case "000e": $tag = "MovementDirectionRef";break; //true or magnetic north
case "000f": $tag = "MovementDirection";break; //positive rational number
case "0010": $tag = "ImageDirectionRef";break; //true or magnetic north
case "0011": $tag = "ImageDirection";break; //positive rational number
case "0012": $tag = "GeodeticSurveyData";break; //text string up to 999 bytes long
case "0013": $tag = "DestLatitudeRef";break; //north or south
case "0014": $tag = "DestinationLatitude";break; //three positive rational numbers
case "0015": $tag = "DestLongitudeRef";break; //east or west
case "0016": $tag = "DestinationLongitude";break; //three positive rational numbers
case "0017": $tag = "DestBearingRef";break; //true or magnetic north
case "0018": $tag = "DestinationBearing";break; //positive rational number
case "0019": $tag = "DestDistanceRef";break; //km, miles, knots
case "001a": $tag = "DestinationDistance";break; //positive rational number
case "001b": $tag = "ProcessingMethod";break;
case "001c": $tag = "AreaInformation";break;
case "001d": $tag = "Datestamp";break; //text string 10 bytes long
case "001e": $tag = "DifferentialCorrection";break; //integer in range 0-65535
default: $tag = "unknown:".$tag;break;
}
return $tag;
}
//=================
// Formats a rational number
//====================================================================
function GPSRational($data, $intel) {
if($intel==1) $top = hexdec(substr($data,8,8)); //intel stores them bottom-top
else $top = hexdec(substr($data,0,8)); //motorola stores them top-bottom
if($intel==1) $bottom = hexdec(substr($data,0,8)); //intel stores them bottom-top
else $bottom = hexdec(substr($data,8,8)); //motorola stores them top-bottom
if($bottom!=0) $data=$top/$bottom;
else if($top==0) $data = 0;
else $data=$top."/".$bottom;
return $data;
}
//=================
// Formats Data for the data type
//====================================================================
function formatGPSData($type,$tag,$intel,$data) {
if($type=="ASCII") {
} else if($type=="URATIONAL" || $type=="SRATIONAL") {
$data = bin2hex($data);
if($intel==1) $data = intel2Moto($data);
if($intel==1) $top = hexdec(substr($data,8,8)); //intel stores them bottom-top
else $top = hexdec(substr($data,0,8)); //motorola stores them top-bottom
if($intel==1) $bottom = hexdec(substr($data,0,8)); //intel stores them bottom-top
else $bottom = hexdec(substr($data,8,8)); //motorola stores them top-bottom
if($type=="SRATIONAL" && $top>2147483647) $top = $top - 4294967296; //this makes the number signed instead of unsigned
if($tag=="0002" || $tag=="0004") { //Latitude
$hour = GPSRational(substr($data,0,16),$intel);
$minutes = GPSRational(substr($data,16,16),$intel);
$seconds = GPSRational(substr($data,32,16),$intel);
$data = $hour+$minutes/60+$seconds/3600;
} else if($tag=="0007") { //Time
$seconds = GPSRational(substr($data,0,16),$intel);
$minutes = GPSRational(substr($data,16,16),$intel);
$hour = GPSRational(substr($data,32,16),$intel);
$data = $hour.":".$minutes.":".$seconds;
} else {
if($bottom!=0) $data=$top/$bottom;
else if($top==0) $data = 0;
else $data=$top."/".$bottom;
}
} else if($type=="USHORT" || $type=="SSHORT" || $type=="ULONG" || $type=="SLONG" || $type=="FLOAT" || $type=="DOUBLE") {
$data = bin2hex($data);
if($intel==1) $data = intel2Moto($data);
$data=hexdec($data);
} else if($type=="UNDEFINED") {
} else if($type=="UBYTE") {
$data = bin2hex($data);
if($intel==1) $num = intel2Moto($data);
if($tag=="0000") { //Latitude
$data = hexdec(substr($data,0,2)).".". hexdec(substr($data,2,2)).".". hexdec(substr($data,4,2)).".". hexdec(substr($data,6,2));
}
} else {
$data = bin2hex($data);
if($intel==1) $data = intel2Moto($data);
}
return $data;
}
//=================
// GPS Special data section
// Useful websites
// http://drewnoakes.com/code/exif/sampleOutput.html
// http://www.geosnapper.com
//====================================================================
function parseGPS($block,&$result,$offset,$seek, $globalOffset) {
if($result['Endien']=="Intel") $intel=1;
else $intel=0;
$v = fseek($seek,$globalOffset+$offset); //offsets are from TIFF header which is 12 bytes from the start of the file
if($v==-1) {
$result['Errors'] = $result['Errors']++;
}
$num = bin2hex(fread( $seek, 2 ));
if($intel==1) $num = intel2Moto($num);
$num=hexdec($num);
$result['GPS']['NumTags'] = $num;
if ($num > 0) $block = fread( $seek, $num*12 );
$place = 0;
//loop thru all tags Each field is 12 bytes
for($i=0;$i<$num;$i++) {
//2 byte tag
$tag = bin2hex(substr($block,$place,2));$place+=2;
if($intel==1) $tag = intel2Moto($tag);
$tag_name = lookup_GPS_tag($tag);
//2 byte datatype
$type = bin2hex(substr($block,$place,2));$place+=2;
if($intel==1) $type = intel2Moto($type);
lookup_type($type,$size);
//4 byte number of elements
$count = bin2hex(substr($block,$place,4));$place+=4;
if($intel==1) $count = intel2Moto($count);
$bytesofdata = $size*hexdec($count);
//4 byte value or pointer to value if larger than 4 bytes
$value = substr($block,$place,4);$place+=4;
if($bytesofdata<=4) {
$data = $value;
} else {
$value = bin2hex($value);
if($intel==1) $value = intel2Moto($value);
$v = fseek($seek,$globalOffset+hexdec($value)); //offsets are from TIFF header which is 12 bytes from the start of the file
if($v==0 && $bytesofdata < $GLOBALS['exiferFileSize']) {
$data = fread($seek, $bytesofdata);
} else {
$result['Errors'] = $result['Errors']++;
}
}
if($result['VerboseOutput']==1) {
$result['GPS'][$tag_name] = formatGPSData($type,$tag,$intel,$data);
$result['GPS'][$tag_name."_Verbose"]['RawData'] = bin2hex($data);
$result['GPS'][$tag_name."_Verbose"]['Type'] = $type;
$result['GPS'][$tag_name."_Verbose"]['Bytes'] = $bytesofdata;
} else {
$result['GPS'][$tag_name] = formatGPSData($type,$tag,$intel,$data);
}
}
}
?>
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