Jonathan: (1) At a conceptual level, I like your suggestions, but I do have a question …
Why have you not used a "cell_measure" attribute in the event_energy data variable to associate this data variable with the event_area data variable as shown in example 7.3 in the CF standard (e.g. :cell_measures = "area: event_area" ? Note that a lightning detection is actually a collection of events, but I thought it was best to work through the lightning detection product one piece at a time. There are other CF convention relevant complexities associated with this lightning detection product I have yet to communicate. (2) Should the CF convention standard be updated to state that a featureType of "point" can make use of cell constructs ? Currently chapter 7 starts "When gridded data does not represent …..". (Note that it may be useful for other discrete sampling geometry types to make use of cell constructs, but I know you are of the thinking to augment the standard on an as-needed basis.) very respectfully, randy On Apr 10, 2012, at 5:20 PM, Jonathan Gregory wrote: > Dear Randy > > Thanks for your further description. Now I agree with you and John that this > is a point feature. I guessed wrongly from your first email that you were > describing something like a timeseries. The file records a number of lightning > events, each with an energy, area, location, time - have I understood > correctly? In that case I suppose the logical structure of the data is > > float event_energy(event); > event_energy:coordinates="time lat lon"; > event_energy:cell_methods="time: sum area: sum"; > float event_area(event); > event_area:coordinates="time lat lon"; > event_area:cell_methods="time: sum area: sum"; > float time(event); > time:bounds="time_bounds"; > float time_bounds(event,two); > float lat(event); > float lon(event); > > Is that right? The energy detected applies to a certain region of space-time, > so I think "sum" is the appropriate cell_methods, rather than being precisely > localised at a particular time and place, in which case "point" would be > right. > I have put the energy and the area of the event as the data variables, and the > time and location as aux coord vars. You might wish to propose new standard > names for the data vars. > > Best wishes > > Jonathan > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > ____________________________________ Randy C. Horne ([email protected]) Principal Engineer, Excalibur Laboratories Inc. voice & fax: (321) 952.5100 url: http://www.excaliburlabs.com _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
