EML

While in the process of documenting eml-entity, I was struck by the fact that
attributeList is required for otherEntityType.

I would like to suggest that entityDescription is a more likely candidate for a
required element that simply importing EntityGroup unmodified.

If, in the absense of an eml=photograph, we are expecting users to use
otherEntity to document photographs, I think that attributeList should be made
optional for OtherEntityType.

On IRC I asked the question, what is the meaning of "attribute" in the context
of a photograph. One answer was, a list of RGB values. That might have utility
for advanced machine processing, but it is not something that a user is going to
fill out. For a non-georeferenced photographs which LTER information managers
have indicated that they consider to be data, a description of the photograph
under entity description makes sense. Saying that a photograph has a single
attribute and that the attribute is either RGB values or even a description of
the photograph itself seems to me to be an artificial imposition of unnessary
structure.

Since otherEntity is by definition a place holder for an entity that we have not
defined, it seems to me that trying to fit it into exactly the same structure as
defined entities is a mistake.