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#86: Allow coordinate variables to be scaled integers
---------------------------------------+------------------------------------
  Reporter:  [email protected]  |       Owner:  
[email protected]         
      Type:  defect                    |      Status:  new                      
             
  Priority:  medium                    |   Milestone:                           
             
 Component:  cf-conventions            |     Version:                           
             
Resolution:                            |    Keywords:  coordinate variables, 
scaled inetegers
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Comment (by Dave.Allured):

 Randy,

 I am concerned that this proposal would require updates and increase
 complexity for many existing Netcdf readers, including general purpose
 software as well as my own code.  In my case, I read coordinate variables
 directly through the Netcdf API, not through a general purpose data
 interface that would automatically unpack.  I have never included the
 unpacking code in my coordinate readers.  I acknowledge that the added
 software complexity would be slight in each individual case, but it adds
 up.

 Also consider that the whole concept of scale/offset packing, just for
 data arrays alone, is confusing to some Netcdf beginners, generating
 significant amounts of user list and help desk traffic.  The latter is in
 part from local experience within my work group.

 For spatial resolution, I would suggest adding a simple non-CF attribute
 such as "resolution = 0.5" or "delta_x = 0.5" or "step = 0.5", or perhaps
 "step_range = 0.44, 0.5" for non-rectilinear coordinates.  IMO this is
 easier for human understanding than "scale_factor = 0.5", for the specific
 purpose that you cited.

 Given that one of your justifications is simplifying writer software, I am
 left wondering whether the value added is worth the trouble.  The status
 quo for coordinate variables seems to be working very well for a long time
 (excepting time coordinates, ouch, different topic).

 Do you have a particular situation where the reduction in file size would
 be significant?  Do you know of any general purpose software that
 '''already''' handles packed coordinate variables?

 --Dave

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Ticket URL: <https://cf-pcmdi.llnl.gov/trac/ticket/86#comment:4>
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