Dear Randy It looks like the resolution you want to indicate is the grid spacing, which you say is homogeneous. Is that right? If so - this may be silly question arising from not remembering what has previously been said - can you not work it out as the difference between any pair of adjacent grid point coordinates?
Best wishes Jonathan ----- Forwarded message from "[email protected]" <[email protected]> ----- > Date: Thu, 9 May 2013 09:56:20 -0400 > From: "[email protected]" <[email protected]> > To: [email protected] > Subject: Re: [CF-metadata] how to capture horizontal spatial resolution of > imagery in a standard way > > > > Folks: > > We have done some more thinking about how to capture the resolution of > gridded observation data (this is a more accurate term than used in previous > posts - imagery) using a to-be-determined CF convention. Note that a key > underlying assumption here is that the gridded data has a homogeneous > sampling interval. > > Originally, I thought a cell_method related approach made sense, but the > resolution of elements in a data variable is not pertinent to the functional > intent of cell methods. > > A suggestion from the board thought that a new coordinate type could be > defined to provide this capability. The problem with this is that data > resolution is not a coordinate, but, rather, a size characteristic of each > element in the data variable containing the gridded observation data. > > > > This brings you back to cells (1st sentence of chapter 7 - When gridded data > does not represent the point values of a field but instead represents some > characteristic of the field within cells of finite "volume," a complete > description of the variable should include metadata that describes the domain > or extent of each cell, and ....) > > > > There are a variety of options available to support this including an > additional syntax for cell boundaries or cell measures, or a new "cell > resolution" that may only be associated with observation data. > > > > The core of any of these approaches would be the specification of a numeric > resolution with its units. Using the existing cell "(interval: value unit)" > as a model, a GOES-R 2 km at nadir gridded product would have an attribute > component that looks like: > > "(resolution: y = 0.000056 rad x = 0.000056 rad)" if it were part of a > broader category (i.e. "bounds:" or "cell_measures"), or > > > > "resolution: y = 0.000056 rad x = 0.000056 rad", if it was not associated > with cell bounds or measures. Note that the syntax to capture the resolution > would need to be flexible to handle the different cell shapes for observation > data. "y" and "x" in these examples are intended to represent the spatial > coordinate variables. > > > > Comments appreciated ! > > > > very respectfully, > > > > randy > > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
