Using Dublin Core – The Elements by Diane Hillman
http://dublincore.org/documents/usageguide/elements.shtml
“Label: Resource Identifier
Element Description: An unambiguous reference to the resource within a given context. Recommended best practice is to identify the resource by means of a string or number conforming to a formal identification system. Examples of formal identification systems include the Uniform Resource Identifier (URI) (including the Uniform Resource Locator (URL), the Digital Object Identifier (DOI) and the International Standard Book Number (ISBN).”
The identifier element may be one of the most essential when it comes to metadata. When thinking about identifiers, the first thing that popped in to my mind was searching for college textbooks. If you have the ISBN or ISSN, you can go to Google, Amazon, BestWebBuys, or any other bookselling resource you can think of and find the required text, and in the correct edition. Finding the correct edition can be very important when it comes to school texts with the same authors over different editions, and having a way to uniquely identify them is important.
In the context of our football images, because they all come from the same game there are going to be a number of similar metadata elements within the set. They are as of yet untitled, but it would be quite possible to have similar titles to the images, or similar titles between this game’s image set and other images from football games. The photographer and other contributors are also likely to be similar throughout the set. Taking all of this into consideration, it becomes very important for one specific photo to have a very unique way of identifying it out of all the rest. As these photos are also now digital objects, they might soon be collected into larger repositories. Having an identifier element to describe them will make finding and positively identifying a specific item easier.
It is difficult for me to think of an argument against the identifier element. A unique way of identifying an item is so essential to maintaining access to that item over time that I can’t see any reason not to include it.