[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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

Hi Patrick, 

OK, how was it "removed"?..just by renaming or by uncompressing?

Our software reads the compressed files, so we do not uncompress them, but 
using "bunzip2" ~should work.

Please see:

http://ams.confex.com/ams/annual2002/techprogram/paper_27449.htm

and

https://www.irads.net/technical.php

and


http://en.wikipedia.org/wiki/Bzip2


Please let us know if you are still having difficulties with the data, or maybe 
you could place some sample files on line for us to peek at.

Cheers,

Jeff Weber


> Okay, the ".nb2" has been removed from the file we receive via LDM.  So
> now if I try to uncompress the nexrad2 file (same header as below) with
> "bunzip2" it still states that the "file is not a bzip2 file".  Is there
> some other decoder that needs to be used to uncompress this file (i.e.,
> what do you use to uncompress these nexrad2 files)?  Could there
> something in the header of this nexrad2 file that is causing this
> problem?  I see the header is different from archived level II data from
> NCDC.
> 
> -Patrick
> 
> Unidata Datastream Support wrote:
> > 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
> > ****************************************************************************
> > Unidata User Support                                    UCAR Unidata Program
> > (303) 497-8642                                                 P.O. Box 3000
> > address@hidden                                   Boulder, CO 80307
> > ----------------------------------------------------------------------------
> > Unidata HomePage                       http://www.unidata.ucar.edu
> > ****************************************************************************
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: JDE-285071
> > Department: Support Datastream
> > Priority: Normal
> > Status: Closed
> >
> >
> >
> 
> 

Jeff Weber
Unidata User Support
http://www.unidata.ucar.edu

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