[Bug 1031] New: - enumeratedDomain doesn't define value order for ordinals

[bugzilla-daemon@ecoinformatics.org]

http://bugzilla.ecoinformatics.org/show_bug.cgi?id=1031

           Summary: enumeratedDomain doesn't define value order for ordinals
           Product: EML
           Version: 2.0.0
          Platform: Other
        OS/Version: other
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: eml - general bugs
        AssignedTo: jones at nceas.ucsb.edu
        ReportedBy: jones at nceas.ucsb.edu
         QAContact: jones at nceas.ucsb.edu
                CC: eml-dev at ecoinformatics.org


Ordinal scale measurements have a discrete list of values with a specific
ordering of those values.  EML does not provide a mechanism for specifying what
this order should be.  We need to add this feature.  Two possible approaches
come immediately to mind:

1) Redefine the "ordinal" element to state that values should be listed in the
code/definition pairs in ascending order.  This has the disadvantage of not
being backwards compatible (ie, some eml-2.0.0 documents might not list them in
this order, and interpreting them in the context of newer versions of eml will
lead to incorrect ordering.

2) add an optional attribute to "codeDefinition" named "order" that is of type
long integer, and make its value correspond to the order of the items.  For
example, for LOW, MEDIUM, HIGH, the order attribute might be "LOW=1, MEDIUM=2,
and HIGH=3.  This is backwards compatible because it is optional.  

I currently see no disadvantages to this approach (2) and so that is what I
recommend at this point.  Feedback appreciated.