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[IDD #TEN-801918]: GEMPAK decoding assistance request

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  • Subject: [IDD #TEN-801918]: GEMPAK decoding assistance request
  • Date: Sat, 14 Mar 2015 18:01:03 -0600
> Good afternoon!
> 
> 
Hi Kevin,

re:
> It looks like I need to do some GEMPAK decoding on the NEXRAD2
> data I am streaming. I am running ldm-6.12.7 and make didn't
> auto-magically build the gempak subdirectory,

Just to be clear, GEMPAK (aka NAWIPS) is a separate package that
we make available.  Installation of the LDM does not automatically
build/install/configure packages other than itself and, if 'configure'
flags are appropriately set, 'gribinsert' and NOAAPort ingest.

re:
thus my decoders directory is empty.

If you want to run GEMPAK decoders, you need to:

- download, build and install GEMPAK

  This is best done as a 'gempak' user and in a GEMPAK-specific directory
  like /home/gempak.

- copy the GEMPAK decoders that were built to a directory (typically 
~ldm/decoders)
  that is in the PATH of the LDM user (typically 'ldm')

re:
> Is there a suggested method to build gempak and get it installed in the
> correct directory?

Yes.  Download and build GEMPAK according to the instructions that are listed
in our GEMPAK pages.

re:
> (I tried make in the gempak directory and it looks like all that got
> created was a library file.)

If you are having problems building GEMPAK, please open a new GEMPAK-specific
inquiry by sending an email to address@hidden.  We will try
to guide through the GEMPAK build and installation process.

re:
> What would a well-formed pqact.conf config line look like for a
> NEXRAD2 gempak pipeline?

The GEMPAK distribution contains an example LDM pattern-action file action
that will concatenate the NEXRAD level 2 pieces into a single file.
I must caution you, however, that the simple GEMPAK processing example
implicitly assumes that the pieces of a full volume scan for a site
will be received in order.  Since the method used by the NWS to distribute
NEXRAD 2 data does not guarantee that the pieces for any volume scan
for a radar will be in order, additional care attention must be placed
on how the pieces are reassembled into a complete volume scan.  We
can broach this subject in detail after you have successfully built
and installed the latest release of GEMPAK.

re:
> Thank you.

No worries.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: TEN-801918
Department: Support IDD
Priority: Normal
Status: Closed