Re: with Descriptor file: ** unknown netCDF error code: -31

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi Steve,
The errror -31 comes from an attempt to read a time step that appears
to Ferret to fall after the end of one cdf file and before the start of the
next. The way a time axis is constructed when you use a descriptor file
is that Ferret uses the information in the descriptor file to build a 
regularly
spaced time axis, using the delta value given in the descriptor.  This
can be inconsistent with what is in the files if you don't have everything
lined up quite right.

Your time unit of 2629746 corresponds to monthly data.  (1/12 of 365.2425
days).  You have

S_START =   1,
S_END   =   239,
S_DELTA =   1,

I assume this corresponds to 20 years of data.  But the time axis is 
computed
using (S_END-S_START-1)/S_DELTA = (239-1)  months.  This is less than
20 years; and that looks to me like it's why you're seeing the error 
message,

WARNING - NON-INTEGER NUMBER OF STEPS PER STEPFILE
INDICATED IN DESCRIPTOR - TRYING TO CONTINUE ANYWAY

Following the suggestion of using a DEFINE AXIS command
to make the axis that you want, and using its steps to
define your axis, if you want:

yes? def axis/t=15-jan-1980:15-dec-1999:1/units=months/t0="15-dec-1979:00:00" tax
yes? list t[gt=tax]

Then this suggests thatyou want S_END to be 240.

Ansley Manke


Steve Cousins wrote:

> I have a series of 20 netCDF files, each with 12 time slices (except the
> last file only has 11 time slices). I have a descriptor file to connect
> these:
>
> &FORMAT_RECORD
> D_TYPE	= '  MC',
> D_FORMAT	= '  1C',
> /
> &BACKGROUND_RECORD
> D_TITLE	= 'BIOLOGY',
> D_T0TIME	= '15-dec-1979 00:00:00',
> D_TIME_UNIT	= 2629746.0,
> D_TIME_MODULO	= .false.,
> /
> &MESSAGE_RECORD
> D_MESSAGE     = ' ',
> D_ALERT_ON_OPEN      = F,
> D_ALERT_ON_OUTPUT    = F,
> /
> &EXTRA_RECORD
> /
> &STEPFILE_RECORD
> S_FILENAME    = '/neptune/usr2/pacific-g-46-99/bio.cdf.001',
> S_AUX_SET_NUM   =           0,
> S_START =   1,
> S_END   =   239,
> S_DELTA =   1,
> S_NUM_OF_FILES  =           20,
> S_REGVARFLAG    = '     ',
> S_INDEX = '                       '
> / 
> &STEPFILE_RECORD
>  S_FILENAME    = '**END OF STEPFILES**'
> /
>
> In ferret I periodically (every 12 slices) get:
>
> 	** unknown netCDF error code: -31
>
> Here is an example:
>
> [ferret@rocky server]# ferret
> 	NOAA/PMEL TMAP
> 	FERRET v5.53  
> 	Linux(g77) 2.4.x - 09/26/03
> 	14-May-04 13:02     
> yes?  set data "/usr2/fer_dsets/descr/bio-g-80-99.des"
> WARNING - NON-INTEGER NUMBER OF STEPS PER STEPFILE
> INDICATED IN DESCRIPTOR - TRYING TO CONTINUE ANYWAY
> yes?  shade/L=1/Z=5/levels=30 co2flx
> yes?  shade/L=12/Z=5/levels=30 co2flx
> ** unknown netCDF error code: -31
> yes?  shade/L=13/Z=5/levels=30 co2flx
> yes?  shade/L=11/Z=5/levels=30 co2flx
> yes?  shade/L=24/Z=5/levels=30 co2flx
> ** unknown netCDF error code: -31
> yes?  shade/L=36/Z=5/levels=30 co2flx
> ** unknown netCDF error code: -31
> yes?  shade/L=48/Z=5/levels=30 co2flx
> ** unknown netCDF error code: -31
> yes?  shade/L=47/Z=5/levels=30 co2flx
> yes?  shade/L=49/Z=5/levels=30 co2flx
>
>
> If I access the file directly (not using the Descriptor file) that
> corresponds to slice 13 I can plot that slice fine.
>
> I can't find what error -31 is.  Anybody have any ideas?
>
> Thanks,
>
> Steve
>
> ______________________________________________________________________
> Steve Cousins, Ocean Modeling Group    Email: cousins@umit.maine.edu
> Marine Sciences, 208 Libby Hall        http://rocky.umeoce.maine.edu
> Univ. of Maine, Orono, ME 04469        Phone: (207) 581-4302
>
>
>