Jim: I agree with Chris. I would say the value calculated is an average of the cell. However, I think the complete syntax should be cell_methods = "time: mean area: mean" v/r rh
---------------------------------------- From: "Chris Barker" <[email protected]> Sent: Thursday, November 21, 2013 5:00 PM To: "Jim Biard" <[email protected]> Cc: "[email protected]" <[email protected]> Subject: Re: [CF-metadata] cell_methods question On Thu, Nov 21, 2013 at 1:03 PM, Jim Biard <[email protected]> wrote: The data is a global grid that has a value for every cell. The values were obtained by fitting a function to a set of irregularly spaced points and then sampling the function at the center of each cell. got it -- sorry for the confusion, that is pretty much what you said the first time... But: at a theoretical level you have a continuous field -- it was sampled at irregular discrete points. You then constructed a regular grid of points by fitting the sample points. So the values you have for each cell is an estimate of the value at the point it was computed. Do its lat-lon is that point, i.e. the lat-lon of the center of the cell. If that's essentially a point value, then you're done. If that's say, a average of the cell, then you would want cell_method: mean But the original points are irrelevant to the this. Of course, you probably want to express that these are results from an interpolation, but I don't know that there's a way to do that in CF -- but it's not cell_methods. -Chris Jim Visit us on Facebook Jim Biard Research Scholar Cooperative Institute for Climate and Satellites NC North Carolina State University NOAA's National Climatic Data Center 151 Patton Ave, Asheville, NC 28801 e: [email protected] o: +1 828 271 4900 On Nov 21, 2013, at 3:59 PM, Chris Barker <[email protected]> wrote: On Thu, Nov 21, 2013 at 9:05 AM, Jim Biard <[email protected]> wrote: I have a variable that contains a time average of gridded temperature measurements. The grid is produced by a fit of irregularly-spaced point data (weather stations), and any given cell might not contain an actual measurement point. I understand that I should have a cell_method of "time: mean" for the time axis, but what should I do for the lat/lon dimensions? Maybe I misunderstand your data, but I think that for this purpose, the "cell" is only in the time dimension -- it is still point data in the lat/lon dimensions. So each value of a given variable is still associated with a single lat and long. So you do the same thing as usual for that. HTH, -Chris Grace and peace, Jim Visit us on Facebook Jim Biard Research Scholar Cooperative Institute for Climate and Satellites NC North Carolina State University NOAA's National Climatic Data Center 151 Patton Ave, Asheville, NC 28801 e: [email protected] o: +1 828 271 4900 _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception [email protected] -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception [email protected]
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