UPCs, EANs, and ISBNs: the verdict

So it gets confusing understanding how these thigns relate. But I think I’ve figured it out, and it’s actually quite simple. By EAN, I mean EAN-13 specifically, which is usually what people mean when they say EAN.

A UPC is just an EAN beginning with 0 (zero), with the initial 0 left off. All EAN’s beginning with 0 are US/Canadian. At some point someone in the US thought, hey, we don’t need to actually interoperate with the rest of the world,  we only care about us, so let’s just leave that 0 off, since all of ours are 0 anyway.  Since n+0=0 (you can call that the ‘arithmetic identity property of zero’ if you want to be fancy), you don’t need to recompute the check digit or anything, just take a UPC, prepend a 0 to it, you’ve got a valid EAN.  Likewise, if you have an EAN beginning with 0, just drop it and you’ve got a UPC.

An ISBN-13 is an EAN.  That’s right, any EAN beginning with 978 or 979 is an ISBN-13, and any ISBN-13 already is an EAN.  Those first few digits in an EAN are a region/country code, but since there are so many books published, books got their own ‘country’ in the EAN Universe, the so-called “Bookland.” (I want to live there!).

So an ISBN-10, to be converted to an EAN, just needs to be converted to an ISBN-13 (including recalculating check-digit).  The move from ISBN-10 to ISBN-13, in addition to adding extra space for ISBNs, also makes them fully legal EANs with no conversion necessary. (That’s why they used 978 and 979 instead of say “1”, and “2” — to make it finally a fully harmonized and valid EAN while they were expanding the address space. Since 978 and 979 are the EAN ‘bookland’ prefixes.).

Phew. Took me a few days of puzzling to figure that out, so maybe it’ll help someone else. Someone correct me if I’m wrong, but I believe I ain’t.

Oh, and on top of all that, it looks like an EAN-13 is now officially called a GTIN-13. Phew. So many names for essentially the same thing.

While we’re on the topic

OCLC/LC standards actually TELL you to put binding information (eg “paperback”) and other “qualification” (eg “vol 1”) right jammed into 020$a with the ISBN. Making it uneccesarily difficult for machine actors to actually pull out the actual ISBN, which they might need, from a bib record.  You might think it would be a lot better to put that info in a different sub-field, and in fact there is a subfield $b for binding information, but it’s “obsolete. do not use.”

What the heck is wrong with us?

Question for the crowd

Is there a canonical way (or any good way) to express an EAN as a URI?

update 5:36pm. Oh boy. I think. Maybe. There’s also something called EPC, which it turns out is a superset of EAN-13.  I think you can losslessly convert an EAN-13 to an EPC, and I think that an EPC may have a canonical URI form.  EPC is intended for use with RFID, and can express more than an EAN-13 (aka a GTIN-13), but I think you can have a valid EPC which is no more or less than a representation of an EAN-13.  But I can’t quite figure out the details.

Confused enough yet?

update again two minutes later. aha! http://tools.ietf.org/html/draft-mealling-epc-urn-02

Still confused. It looks like you can have a URN for a GTIN (aka EAN-13?) like for example this:

urn:epc:id:sgtin:900100.0003456.1234567

But you do need those periods. And only the first two groups of numbers corresopnd to the EAN-13.  In that case, the EAN0-13, would, I think, be 9001000003456.  That next number is some extra info (I think identifying the particular item in FRBR-speak, the actual individual physical thing). What if you don’t have the extra info, can you still make a GTIN URN? I could be wrong about a GTIN being the same thing as an EAN-13. Very confused.

And lastly…

Using the good folks at O’Reilly as an example, it looks like urn:epc:id:gtin (instead of sgtin) can be used to represent a standard GTIN-13.

See:

http://opmi.labs.oreilly.com/product/9780596521677

<dc:identifier>urn:epc:id:gtin:063692.0015396</dc:identifier>

Except what I don’t understand is why they supply an ISBN-13 which appears to be different. Based on my understanding that GTIN-13 == EAN-13 == ISBN-13, the ISBN-13 should be the same… and yet it is not…

<dc:identifier>urn:isbn:9780596153960</dc:identifier>

So I still remain confused. But looks like the folks at O’Reilly might be good to talk to.

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3 thoughts on “UPCs, EANs, and ISBNs: the verdict”

  1. Actually, 979 is Musicland. Bookland annexed seized most of musicland after a brief war. Reservations were set up for native musiclandians.

  2. UPC actually came before EAN. As UPC was not really useful outside of North America the Europeans created EAN to be backwards compatible with UPC.

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