The allure of using add_offset & scale_factor with coordinate variables goes beyond saving space. For example, in our use case …
(1) Makes the s/w producing the product simpler. (2) The scale_factor also tells you what the horizontal spatial resolution is in a representation that aligns with the coordinate space. very respectfully, randy On Apr 10, 2012, at 3:11 PM, Etienne Tourigny wrote: > If netcdf-4 is an option for you, it might be simpler to compress > (deflate) the coordinate variables, this works transparently. > > Etienne > > On Tue, Apr 10, 2012 at 2:40 PM, David Hassell > <[email protected]> wrote: >> Hello Randy, >> >> I, too, recently thought about this when working on some CF processing >> software (cf-python), but couldn't think of a use case so didn't >> pursue it - and now you have one! >> >> It seems to me that the use of scale_factor and add_offset is intended >> for (but not restricted to ...?) the reduction of dataset size >> (chapter 8). Is the requirement in your example for space saving, or >> some other convienience? I personally think that the latter case is >> better served by an appropiate setting of the units attribute (such as >> units="0.555555555555556 K @ 459.67" if we have converted from Kelvin >> to Fahrenheit). >> >> Anyway, I can't think of a reason not to allow these attributes on >> coordinates - these variables can be very large, after all. >> >> All the best, >> >> David >> >> ---- Original message from Randy Horne (01PM 05 Apr 12) >> >>> Date: Thu, 5 Apr 2012 13:05:45 -0400 >>> From: Randy Horne <[email protected]> >>> To: [email protected] >>> X-Mailer: <IMail v8.21> >>> Subject: [CF-metadata] Using add_offset & scale_factor with coordinate >>> variables >>> >>> Folks: >>> >>> Appendix A, Table A.1 in the CF conventions state that add_offset and >>> scale_factor can be used with data variables, but not coordinate variables. >>> >>> For the data producing system I am working (GOES-R Ground Segment) it is >>> particularly convenient to make use of add_offset and scale_factor with our >>> coordinate variables. >>> >>> Is there an issue with changing the conventions to allow this ? >>> >>> very respectfully, >>> >>> randy >>> >>> >>> >>> >>> ..............End of Message ...............................--> >>> >>> >>> >>> >>> _______________________________________________ >>> CF-metadata mailing list >>> [email protected] >>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> >> >> -- >> David Hassell >> National Centre for Atmospheric Science (NCAS) >> Department of Meteorology, University of Reading, >> Earley Gate, PO Box 243, >> Reading RG6 6BB, U.K. >> >> Tel : 0118 3785613 >> Fax : 0118 3788316 >> E-mail: [email protected] >> _______________________________________________ >> 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
