hi Thomas
Not so much ignored, as not so sure how to respond to it.
I'm *very* interested in getting a suitable solution.
All the answers I can come up with imagine an extension to CF ... (it'd require a pretty minor extension to cell bounds and/or cell measures) so I'm interested to know if anyone thinks we can do it in another way that we haven't spotted.
Cheers
Bryan
On Wednesday 17 February 2010 13:36:21 Thomas Lavergne wrote:
> Dear all,
>
> I do not think someone reacted on my concern/question about non-polygonal cell boundaries. Maybe I am the only one with this issue or maybe this topic went un-noticed because of heavy load on the CF list at that time.
>
> I thus re-post my original message in hope that someone will comment on it (or point me to an archived thread that I did not yet see).
>
> Original post:
>
> > Hi everyone,
> >
> > I refer to Chapter 7 on "Data Representative of Cells", 7.1 "Cell
> > Boundaries".
> >
> > The specification of those boundaries seems to biased towards
> > polygonal boundaries (in the case of a 2D surface). This covers
> > certainly most of the needs but what happens if the cell is defined as
> > a disc of radius x km (with center at the coordinate value)?
> >
> > Of course, I can always give 10 to 10,000 vertices that will
> > approximate my disc but it does not sound very neat nor efficient. We
> > would have to somehow move away from listing the 'bounds' and start
> > describing the shape of the cell (disc, ellipse, rectangle, etc...).
> > Note that the concepts of "cell measures" and "cell methods" would
> > still perfectly hold.
> >
> > One example of such a dataset would be one where at each grid location
> > we report the mean/minimum/maximum temperature or pressure recorded by
> > any station found in a radius of, say, 30 km around the central
> > point.
> >
> > Another example is satellite data in swath projection where each
> > record is associated to a Field Of View, which is often approximated
> > as a an ellipse.
> >
> > Did someone give it a thought already?
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--
Bryan Lawrence
Director of Environmental Archival and Associated Research
(NCAS/British Atmospheric Data Centre and NCEO/NERC NEODC)
STFC, Rutherford Appleton Laboratory
Phone +44 1235 445012; Fax ... 5848;
Web: home.badc.rl.ac.uk/lawrence
Received on Thu Feb 18 2010 - 04:58:45 GMT
