Hello,

I'm trying to create a MODS framework for a collection of photos of ships, 
and I'm hoping that the user community can help me with the use of the 
authorityURI and valueURI attributes.

The photos can contain multiple ships, each of which has several descriptive 
elements. To achieve this we're mapping along the following lines:

Ship 1:
<subject>
<name></name>
<genre></genre>
<occupation></occupation>
<temporal></temporal>
</subject>

Ship 2:
<subject>
<name></name>
<genre></genre>
<occupation></occupation>
<temporal></temporal>
</subject>

This seems fairly straightforward. Where things get complex is in the 
temporal element.

Each ship has three dates associated with it - the build date, commissioned 
date and the decommissioned date. As there is no display label attribute in 
the temporal sub-element, we're looking at using authorityURI and valueURI. 
In this case, the authority is us (my library) and the values are "built 
date", "commissioned date" and "decommissioned date". 

This would look like:

<subject>
<temporal authorityURI="http://library.unsw.edu.au/vocabulary" 
valueURI="http://library.unsw.edu.au/vocabulary#builtDate">1968</temporal>
<temporal authorityURI="http://library.unsw.edu.au/vocabulary" 
valueURI="http://library.unsw.edu.au/vocabulary#commissionedDate">1969</temp
oral>
<temporal authorityURI="http://library.unsw.edu.au/vocabulary" 
valueURI="http://library.unsw.edu.au/vocabulary#decommissionedDate">1980</te
mporal>
</subject>

The questions we have are:
1. Can authorityURI and valueURI be specified at the lower sub-element? The 
examples we found all have it at the top level element.
2. If one specifies the valueURI, are we right in thinking that one still 
needs the actual element value between the tags? (In the example above, that 
would be the "1968" bit.)
3. Is this a correct use of the authorityURI and valueURI attributes? Have 
we done anything wrong with this mapping?

We've been pouring over the guidelines and we're still unsure of the answers 
to these questions. I hope someone in the community can help us out!

Alyson Dalby
Library Repository Services, UNSW Australia