Dear Bob, At this stage, we are very interested in exploring GUID use-cases, specially those that may impose special requirements to the system. What you briefly described has the potential to fall into that category. Would you mind elaborating a bit on it? First of all, I think it is important to record that images and multimedia objects in general can be represented as actual data in LSIDs for example (as opposed as the other data objects for which we are planning on using only metadata). You also raise the question of what gets a GUID, which seems to be a recurrent issue for GUIDs in general. I would say that whatever objects that are useful to applications can get an id. In other words, if it is important to identify individual pieces of a composite object, then it's fair to issue GUID to them and link them all in the metadata. The metadata would also tell what is the object type (the whole or each part). Is that applicable to your case? Finally, I don't quite understand the following sentence: "JPEG2000 presents special problems because its serializations can have multiple media and XML packages in a single file." Could you elaborate on it? Regards, Ricardo PS.: If you'd like, you can create a new use-case directly on the GUID Wiki, on the following page: http://wiki.gbif.org/guidwiki/wikka.php?wakka=GUIDUseCases. If you decide to enter a new use-case in that page, you may as well create another category for them (such as Multimedia objects or descriptive data). If you'd rather elaborate on this on the list, I can summarize your comments on the wiki later. Bob Morris wrote:

Somewhere in a monitoring and/or a descriptive data breakout or both, don't forget to consider multimedia objects. JPEG2000 presents special problems because its serializations can have multiple media and XML packages in a single file. All are addressable with internet URLs which depend on the server offering the file. Which gets the GUID, the file object or the content pieces? This must be a generic GUID problem for composite objects.

Sounds like an interesting party. Kevin will bring me the news when we meet up in Agadir.

Bob