I would agree strongly with Jeff. Actually I think he is extending the original idea of Confucius. Few people know that when he said "Every journey starts with a few steps" he was really talking about software development projects or that he then said "and it is really hard to turn around!".
Starting with this very small set of metadata fields is particularly ironic when we hear so many people complaining about the lack of "Use Metadata" that they need to actually do something with the data. I would expect that LDM is a use metadata rich environment. To bad to lose it all.
A bunch of links to metadata crosswalks at: http://www.ukoln.ac.uk/metadata/interoperability/
Information on the remote sensing extensions to FGDC that you are going to need for the types of data you are interested in: http://www.fgdc.gov/standards/status/csdgm_rs_ex.html. Somewhere I had a PPT on this extension, but I can't track it down electronically...
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