[gradsusr] Cannot Contour Grid - all undefined values error

Tue Jun 6 13:16:31 EDT 2017

Bill,

I had no problems plotting the efi* and pctile* files.  This is not to brag
to to say that with a little more understanding, you can start making plots!

g2ctl is a simple program.  When you make a ctl file from a single grib
file,
it looks for the records with the earliest, second earliest and last time
stamp.  For example,

earliest time stamp:   00Z jan 1 2017
next time stamp:        06Z jan 1 2017
last time stamp:         18Z jan 2 2017

>From these three time stamps, g2ctl knows

   1) data starts at 00Z jan 1 2017
   2) dt=6 hours
   3) number of time steps = 8
       -> grads ctl file:  tdef 8 linear 00Z01jan2017 6hr

If you have data at 07Z jan 1, 2017, gribmap will ignore it because it is
expecting data
every 6 hours.

g2ctl needs to make a list of variables for the control file.  To save
time, g2ctl
makes the variable list from the first and second time steps.  If the 3rd
time step
and a new variable, g2ctl will not find it.  Since you are  combining efi*
and pctile*
files, this may have happened.

The GrADS data model only has one time dimension.  For example,

   default mode:    analysis at 00Z Jan 3 2017  has the same time as
                             24 hour forecast from 00Z Jan 2, 2017.

To get around this problem, you have to be careful that g2ctl and gribmap
using the same time mode.  For your files,

default:  (no option) use verification time (end of time average)
-0:          use start of forecast (initial time)
-b:          use start of time average

For my test, I used the -b mode.

When you make your files, you should either make

    cat pctile.2017060200.* >pctile.2017060200.grib2
or
    cat pctile.*.000_to_024hrs.grib2 >pctile.000_to_024hrs.grib2

Combining pctile and efi files is asking for trouble.

Wesley Ebisuzaki

On Tue, Jun 6, 2017 at 11:50 AM, Jennifer M Adams <jadams21 at gmu.edu> wrote:

> There is no need to apologize for being a novice. You may find this doc
> page on how GrADS deals with GRIB data useful:
> http://cola.gmu.edu/grads/gadoc/grib.html
> Please see more comments inline.
>
>
> > On Jun 6, 2017, at 11:34 AM, William Rasch - NOAA Federal <
> william.rasch at noaa.gov> wrote:
> > I grabbed one of the files, only one, then cat'ed that to the efi.master
>
> I would haved run g2ctl on just the one file, before cat’ing it to
> efi.master.
>
> >
> > Ran:  g2ctl  efi.master.ctl
> >
> > Then, did a gribmap -v efi.master.ctl
> >
> > It then prompted me the "descriptor file", and I entered:  efi.master.ctl
> >
> > The feedback from that was this:
>
> In general, it would be better to send the actual text instead of an image
> of it.
>
> >
> > <image.png>
> It doesn’t look you got a MATCH for any of the records in your file.
> What is in your descriptor file?
>
> —Jennifer
>
> >
> > I then tried to display tmp2m and got the same error.
> >
> > Thanks for any additional help and again, sorry for my incompetence with
> this.
> >
> > Bill
> >
> > On Mon, Jun 5, 2017 at 6:20 PM, Jennifer M Adams <jadams21 at gmu.edu>
> wrote:
> > Hi, Bill -
> > I find that the g2ctl output often needs a few tweaks to get evertyhing
> right and some variables need a fourth grib code in the units field in
> order to match properly. You also appear to be concatenating files with
> different time stamps and this may be confusing the issue. Try setting up
> your descriptor with only one file, and run gribmap in verbose mode (with
> the -v) and look at what is matching/not matching. If records don’t match
> what’s in your descriptor, gribmap will show you what the entry should
> contain. Once you are matching all the records in one file, then add the
> templating for multiple time steps. If it’s still not working please send
> your descriptor and the gribmap verbose output.
> > —Jennifer
> >
> >
> >
> > On Jun 5, 2017, at 11:33 AM, William Rasch - NOAA Federal <
> william.rasch at noaa.gov> wrote:
> >
> > > Hi,
> > >
> > > I have what would seem to be a very simple data-set and "variable" I'm
> trying to plot wiht GrADS.
> > >
> > > The grib files are located here...
> > >
> > > ftp://ftp.cdc.noaa.gov/Public/gbates/reforecast2/efi_grib2/
> pctile.2017060500.000_to_024hrs.grib2
> > >
> > > I am simply downloading several of these files, then do this:
> > >
> > > cat * > efi.master
> > > g2ctl efi.master > efi.master.ctl
> > > gribmap -i efi.master.ctl
> > >
> > > I'm simply trying to plot either:
> > >
> > > temp2m
> > > wind10m
> > > apcpsfc
> > >
> > > When I try to display the data, I get the error:
> > >
> > > Cannot Contour Grid - all undefined values
> > >
> > > Thanks for any help....
> > >
> > > Bill
> > > _______________________________________________
> > > gradsusr mailing list
> > > gradsusr at gradsusr.org
> > > http://gradsusr.org/mailman/listinfo/gradsusr
> >
> > --
> > Jennifer Miletta Adams
> > Center for Ocean-Land-Atmosphere Studies (COLA)
> > George Mason University
> >
> >
> >
> >
> > _______________________________________________
> > gradsusr mailing list
> > gradsusr at gradsusr.org
> > http://gradsusr.org/mailman/listinfo/gradsusr
> >
> >
> >
> > --
> >
> > William Rasch
> > Science and Operations Officer
> > Weather Forecast Office
> > Sacramento, CA
> > _______________________________________________
> > gradsusr mailing list
> > gradsusr at gradsusr.org
> > http://gradsusr.org/mailman/listinfo/gradsusr
>
> --
> Jennifer Miletta Adams
> Center for Ocean-Land-Atmosphere Studies (COLA)
> George Mason University
>
>
>
>
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> gradsusr mailing list
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>
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