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? > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > -- 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 _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
