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[Datastream #JDE-285071]: LDM nexrad level II file extension

Hi Patrick,

re:
> My university is a 2nd tier site for NEXRAD data.  We have the LDM setup
> and are receiving nexrad level 2 files, but I am unfamiliar with the
> file extension, ".nb2".  The header for one file has the form:
> 
> 0000000   A   R   2   V   0   0   0   1   .   4   0   8  \0  \0   6 241
> 0000020 004 265 027 350   K   O   H   X  \0  \0   . 273   B   Z   h   3
> 
> But when I open try to uncompress the file (%] bunzip2  file.nb2) I get
> this error stating it is not a bzip2 file.  So what kind of file is
> this?  Thanks.

The NEXRAD Level II data is sent as pieces of products, not as entire files.
The naming of the pieces/files will be governed by the pattern-action entry
that someone at UAH has setup.  You should contact that person to find out
why the files are named with a .nb2 suffix.

We process the NEXRAD Level II data by:

- writing the pieces to a hidden file as they are received
- when the final piece comes in for a product, the piece is written and
  the file is renamed to no longer be hidden.

Here are the pqact.conf entries we use to accomplish this:

# level2 radar from CRAFT  feed
#
CRAFT   ^L2-BZIP2/(....)/([0-9][0-9][0-9][0-9][0-1][0-9][0-3][0-9])([0-2][0-9][0
-5][0-9])([0-9][0-9])
        FILE    data/pub/native/radar/level2/\1/\2/.Level2_\1_\2_\3.ar2v
#
#
# Done to move file after last record is received "/E" to prevent
# autoupdate from seeing partially received files (dccraft_move is a
# shell script copied from $NAWIPS/bin/scripts)
CRAFT   ^L2-BZIP2/(....)/([0-9][0-9][0-9][0-9][0-1][0-9][0-3][0-9])([0-2][0-9][0
-5][0-9])([0-9][0-9])/[0-9]*/[0-9]*/E
        EXEC    util/dccraft_move data/pub/native/radar/level2/\1/\2/.Level2_\1_
\2_\3.ar2v data/pub/native/radar/level2/\1/\2/Level2_\1_\2_\3.ar2v

Notice that we use the suffix '.ar2v'.  It means nothing outside of it reminds
us that the file is an archive of Level 2 NEXRAD data.  The data inside the
file are left as received: in bzip2 compressed format.

Please let us know if this information helps...


> --
> -Patrick
> ___________________________________
> Patrick Gatlin
> Research Associate
> Earth Systems Science Center
> University of Alabama in Huntsville
> 320 Sparkman Drive
> Huntsville, AL  35805
> e-mail: address@hidden
> phone: (256)-961-7910
> 
> 

Cheers,

Tom
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Ticket Details
===================
Ticket ID: JDE-285071
Department: Support Datastream
Priority: Normal
Status: Closed