undef with unpack in dtype netcdf

[Diane Stokes]

Hi,

I'm running GrADS 1.9b3 on AIX:

Config: v1.9b3 32-bit big-endian readline sdf/xdf netcdf lats printim


I'm trying to help someone here read a netcdf file, using the new "dtype
netcdf" entry in the data descriptor file.  This data includes a packed
variable, temp.

The data descriptor file and output from ncdump -c are attached.

When I include the "upack" line in the descriptor file, temp displays
correctly *except* for the fact that the missing points are not masked
out.  GrADS sees these values as -10.0017.

If I remove the "undef" line, the missing values are seen as -32768 and
are masked out correctly, but, of course, the wrong values are displayed
for the temperature (because they haven't been unpacked).

Is the problem that GrADS is expecting -32768 but seeing -10.0017?  Or
might it be a roundoff issue, eg, GrADS is expecting -10, but seeing
-10.0017?  Either way, any suggestions?

We could use sdfopen to read one file, but we are templating a time
series of files.  We have to use "dtype netcdf" instead to avoid core dumps.

Maskout will work in the meantime, but that is not an ideal solution.



*ALSO*, I can display the non-packed packed variables version using
gradsnc.  I get, eg:

ga-> d eta_t
Warning: Scale Factor Attribute Value Not Retrieved ... setting to 1.0
Warning: Offset Attribute Value Not Retrieved ... setting to 0.0
Contouring: -1.8 to 0.6 interval 0.3

But with gradshdf, I get:

ga-> d eta_t
ncattget: ncid 4: Attribute not found

and GrADS exits. (No core dump).

I'll start a new thread with this one if you like, but then you'd get
another copy of the same ncdump -c output.

   Thanks in advance for any help.
      Diane

--
Diane Stokes
Environmental Modeling Center
National Weather Service/NOAA

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