Method to write LocationShown and LocationCreated in IPTC Extension schema

[amarlakhani]

Per https://exiv2.org/tags-xmp-iptcExt.html and the associated IPTC Extension specifications, the value type of LocationShown and LocationCreated is a LocationDetails bag. The resulting Xmp section would look something like:

<Iptc4xmpExt:LocationCreated>
  <rdf:Bag>
    <rdf:li rd:parseType=“Resource”>
      <Iptc4xmpExt:Sublocation/>
      <Iptc4xmpExt:City>Paris</Iptc4xmpExt:City>
      <Iptc4xmpExt:ProvinceState/>
      <Iptc4xmpExt:CountryName>France</Iptc4xmpExt:CountryName>
      <Iptc4xmpExt:CountryCode/>
      <Iptc4xmpExt:WorldRegion/>
    </rdf:li>
  </rdf:Bag>
<Iptc4xmpExt:LocationCreated>

I haven't been able to find anything in the docs that would allow keys to be nested within a Bag like this.

If there is a way, I would be grateful if somebody would be able to share it with me.

[clanmills]

I don't know anything about this. However, I'm writing a book Image Metadata and Exiv2 Architecture. Here's the current draft: https://clanmills.com/exiv2/book

I intend to start work for the book on IPTC in next week or two. I've been working on Exiv2 for 12 years and most of my effort has been focused on bugs, build and test. The IPTC code is very stable, so I don't know much about it! The XMP code is the Adobe XMPsdk 4.4.0 and you can build/link more recent Adobe offerings.

I will investigate.

[clanmills]

There have been a few discussions about this in years gone by. For example:

https://dev.exiv2.org/boards/3/topics/2016?r=2025#message-2025

As you can see, Scott Renton concluded that "we're heading in the right direction now", although to be honest, I didn't really know what we were discussing! I recommend that you use the search on the "old" bug tracker and you might find what you want.

[clanmills]

I'm pretty sure that your answer is in the discussion with the person at the University of Edinburgh. If you agree, could you close this issue please. If you need further assistance, I will try to help although I really don't know much about XMP and/or IPTC.

[amarlakhani]

Thanks for your help Robin. It doesn't look like we can do exactly what I was looking for in Exiv2 but no worries, I think it's fair to say that this seems like more of a job for Adobe's XMP Toolkit. I'll close the issue.

[clanmills]

I'm glad to not have this sitting "on my plate". Thanks for closing this.

If you can do this with XMPsdk, it's probably possible to do it from Exiv2 which mostly puts an Exiv2 veneer over XMPsdk. I don't want to increase the scope of the book, however I will think about adding a chapter to discuss XMP as I haven't found Adobe's documentation to be very illuminating.

The primary focus of the book is to deal with file formats and to explain how the metadata is stored in the image and how it is parsed.

[clanmills]

I've done the following:

566 rmills@rmillsmbp:~/temp $ curl -OL http://clanmills.com/Stonehenge.jpg
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 6599k  100 6599k    0     0  85456      0  0:01:19  0:01:19 --:--:-- 80968
https://github.com/Exiv2/exiv2/issues/1254
567 rmills@rmillsmbp:~/temp $ exiv2 -M'set Xmp.iptc.LocationCreated XmpBag something' Stonehenge.jpg 
568 rmills@rmillsmbp:~/temp $ exiv2 -pX Stonehenge.jpg | xmllint --pretty 2 -
exiv2 -pX Stonehenge.jpg | xmllint --pretty 1 -
<?xml version="1.0"?>
<?xpacket begin="" id="W5M0MpCehiHzreSzNTczkc9d"?>
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="XMP Core 4.4.0-Exiv2">
  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
    <rdf:Description xmlns:xmp="http://ns.adobe.com/xap/1.0/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:Iptc4xmpCore="http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/" rdf:about="" xmp:Rating="0" xmp:ModifyDate="2015-07-16T20:25:28+01:00">
      <dc:description>
        <rdf:Alt>
          <rdf:li xml:lang="x-default">Classic View</rdf:li>
        </rdf:Alt>
      </dc:description>
      <Iptc4xmpCore:LocationCreated>
        <rdf:Bag>
          <rdf:li>something</rdf:li>
        </rdf:Bag>
      </Iptc4xmpCore:LocationCreated>
    </rdf:Description>
  </rdf:RDF>
</x:xmpmeta>
<?xpacket end="w"?>
569 rmills@rmillsmbp:~/temp $ 

So it created the bag and added something. We want to edit that now to be what you discussed above.

<Iptc4xmpExt:LocationCreated>
  <rdf:Bag>
    <rdf:li rd:parseType=“Resource”>
      <Iptc4xmpExt:Sublocation/>
      <Iptc4xmpExt:City>Paris</Iptc4xmpExt:City>
      <Iptc4xmpExt:ProvinceState/>
      <Iptc4xmpExt:CountryName>France</Iptc4xmpExt:CountryName>
      <Iptc4xmpExt:CountryCode/>
      <Iptc4xmpExt:WorldRegion/>
    </rdf:li>
  </rdf:Bag>
<Iptc4xmpExt:LocationCreated>

[clanmills]

Progress:

628 rmills@rmillsmbp:~/temp $ cp ~/Stonehenge.jpg .
629 rmills@rmillsmbp:~/temp $ exiv2 -M'set Xmp.iptc.LocationCreated XmpBag something' Stonehenge.jpg 
630 rmills@rmillsmbp:~/temp $ exiv2 -M'set Xmp.iptc.LocationCreated[1] London' Stonehenge.jpg 
631 rmills@rmillsmbp:~/temp $ exiv2 -M'set Xmp.iptc.LocationCreated[2] Paris' Stonehenge.jpg 
632 rmills@rmillsmbp:~/temp $ exiv2 -pX Stonehenge.jpg | xmllint --pretty 1 -
<?xml version="1.0"?>
<?xpacket begin="" id="W5M0MpCehiHzreSzNTczkc9d"?>
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="XMP Core 4.4.0-Exiv2">
  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
    <rdf:Description xmlns:xmp="http://ns.adobe.com/xap/1.0/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:Iptc4xmpCore="http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/" rdf:about="" xmp:Rating="0" xmp:ModifyDate="2015-07-16T20:25:28+01:00">
      <dc:description>
        <rdf:Alt>
          <rdf:li xml:lang="x-default">Classic View</rdf:li>
        </rdf:Alt>
      </dc:description>
      <Iptc4xmpCore:LocationCreated>
        <rdf:Bag>
          <rdf:li>London</rdf:li>
          <rdf:li>Paris</rdf:li>
        </rdf:Bag>
      </Iptc4xmpCore:LocationCreated>
    </rdf:Description>
  </rdf:RDF>
</x:xmpmeta>
<?xpacket end="w"?>
633 rmills@rmillsmbp:~/temp $ 

[amarlakhani]

Thank you for the help so far! I'm trying from my end too but obviously can't quite match your expertise.

[clanmills]

I assure you that I have no expertise with this. I'm floundering in the dark. I think I know everything about image formats and how Exif and ICC is stored and manipulated. The XMPsdk is however a total mystery to me. I know even less about IPTC - although at least IPTC is on my TODO list for the book.

I've had another idea. If we express this in IPTC, the convertor magic will probably move it into XMP. I'm looking at the test and sample code for IPTC.