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[IDV #SFH-774567]: aggregating grb files

Hi HP,

> Was good to hear you on the phone yesterday.

I agree; it seems like a long time since we talked!

> I have recently tried to aggregate a bunch of grb files in McV/IDV - to
> no avail. Two sample are attached.  The files contain two data records,
> proj0 and proj1. The record of interest is proj1, rain rate derived from
> MSG data. The proj1 data displays correctly for a single file
> (multiplying the values by 3600 you get mm/hr), but the files do not
> aggregate. John Caron, asked by TomW, gave the hint to extract the proj1
> records and put them into one file. However, he did not give any hint
> how to accomplish this, and he has not answered (yet?) to a second email
> by me. I am at a loss (and somehow TomW as well). Any ideas how to do it
> or to get something out of the netCDF people. This would be really great!

As you have no doubt guessed, I redirected your email to me into the IDV area
of our inquiry tracking system so that it could be tracked properly...

Yuan and I got together to see if there was some way we could use the IDV
to extract the instantaneous precipitation rate fields from the two GRIB
files you provided and write them into one or two netCDF files.  Our attempts
failed because the code that is used to do the writing is not smart enough
to recognize that there is only one field in the group that contains the
instantaneous precipitation rate.  While we were playing with your GRIB files,
John came into the room (we were working in our conference room which is in
the last stages of being setup for the series of training workshops that
start this coming Monday).  John explained why the write-to-netCDF file
was failing let us know that the next version of TDS/CDM will contain code
that can handle the aggregating of fields organized by groups in netCDF files.

Sometime this afternoon, John is going to show Yuan how to use the new, 
version of the ToolsUI to extract the instantaneous precipitation rate fields
from your GRIB files and write them into one or more netCDF files.  The 
output will solve the immediate problem of aggregating the fields, but, of 
will not solve the more general problem of doing this for arbitrary files.
If you are interested, we can provide the new, unreleased version of the ToolsUI
to you and describe the procedure for doing the extraction.  The "real" solution
will be when the new TDS/CDM code is released and a new version of the IDV is
made that uses that new TDS/CDM code.  Exactly when this might be is not known
at the moment.  Our ability to get out new releases of the IDV are being 
by some lingering and strange problems with SVN that cropped up after the 
of our file server after it crashed this past Monday AND our impending series
of training workshops.

> yesterday swimming pool and today tropical downpours, HP

We had a very nice downpour yesterday afternoon here in Boulder (any moisture
is very welcome by all), and we are expecting more of the same this 
So far the summer has been very nice despite some fires that have broken out
near Boulder (in the foothills just west of north Boulder, and outside of Lyons
which is to the north of Boulder).

Talk to you later...


Unidata User Support                                    UCAR Unidata Program
(303) 497-8642                                                 P.O. Box 3000
address@hidden                                   Boulder, CO 80307
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Ticket Details
Ticket ID: SFH-774567
Department: Support IDV
Priority: Normal
Status: Open

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