My 2c about URNs:
URNs are just a piece of string like any other string. Difference is
that semantic tools could be use to write/read/infer more information
about a string that is a URI (URNs are URIS). For example I could
easily write (e.g. in RDF) property value pairs about a URN, that
will allow me to encode information to help me plot the data. And, as
Benno was pointing out it could be use to alternate representations
of the same information.
-Luis
On Oct 3, 2007, at 5:06 PM, mcginnis at ucar.edu wrote:
>> I think that the description of the coord ref system in terms of
>> projection,
>> ellipsoid and vertical datum can't be dispensed with until the day
>> when it is
>> no more difficult to look it up on the net than it is to read it
>> directly from
>> the file. Until then, the information has to be in the file to
>> make the file
>> self-describing, and I would say that day is a long way off, when one
>> considers
>> all the applications, some of them simple user-written programs,
>> that want to
>> use the netCDF files.
>
>
> I think this is a really important point.
>
> Consider that "just as easy to look it up on the net" implies not only
> that users whose systems are not URN-aware can find out where to look
> without much effort, but also that systems using NetCDF data have a
> net
> connection that can quickly and reliably reach a server providing that
> information.
>
> A URN is great if you're sitting at your desk using a program that
> will
> look it up for you. If you're *writing* a program that does something
> with the data, or if you're working someplace without easy internet
> access, or if for some reason your net connection can't get to
> whatever
> OGC site defines it, the URN may be no better than saying simply
> 'geoid
> = "WGS 1984"'. (Pity the hypothetical programmer working on code for
> an autonomous submersible that talks to data-collection buoys...)
>
> Cheers,
>
> Seth
>
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Received on Wed Oct 03 2007 - 19:33:02 BST
