Comments on: Structure Images on ChemSpider Tagged for InChI Searching. Web Service Enabled.

By: Tony Hammond

Tony Hammond — Wed, 10 Oct 2007 11:35:18 +0000

Hi Antony:

Gotta ask, but why not XMP? That IMHO is the way forward to getting extensible metadata in XML (RDF/XML to boot) into media files:

“An XMP Packet is embedded in a PNG graphic file by adding a chunk of type iTXt. This
chunk is semantically equivalent to the tEXt and zTXt chunks, but the textual data is in the
UTF-8 encoding of the Unicode character set, instead of Latin-1.

The Chunk Data portion is the XMP Packet. The packet must be marked as read-only.”

Details on p.97, XMP Spec:
http://www.adobe.com/devnet/xmp/pdfs/xmp_specification.pdf

Cheers,

Tony

By: Developer at ChemSpider

Developer at ChemSpider — Tue, 25 Sep 2007 06:29:12 +0000

Tags above were chosen mostly arbitrarily. I still can’t find any pointers on which keywords should be used for tEXt. Any attempt to standardize? Any example of libpng direct usage for storing cheminfo? Any hints where/how IIOMetadata gets stored in PNG? What about other image formats?

By: Rich Apodaca

Rich Apodaca — Tue, 25 Sep 2007 04:46:03 +0000

For those do-it-yourselfers out there, many programming languages support reading and writing PNG image metadata:

http://depth-first.com/articles/2007/08/29/never-draw-the-same-molecule-twice-writing-png-image-metadata-with-python

http://blog.modp.com/2007/08/python-pil-and-png-metadata-take-2.html

http://baoilleach.blogspot.com/2007/08/access-embedded-molecular-information.html

http://chem-bla-ics.blogspot.com/2007/08/jchempaint-too-png-embedded.html