[CF-metadata] URNs

From: mcginnis at ucar.edu <mcginnis>
Date: Wed, 3 Oct 2007 18:06:59 -0600

> 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 - 18:06:59 BST