Re: 20051026: NCDC to Unidata NEXRAD II converter

Art,

The uncompressed file below should work if you place it in a directory under
$RAD such as: $RAD/ncdc/KPBZ/KPBZ_YYYYMMDD_HHNN
This would match the sample entries for the IDD stream which uses
$RAD/craft/SITE/SITE_YYYYMMDD_HHNN.

The key for NMAP is that the file have the DIR_YYYYMMDD_HHNN template.
The text interface programs should be able to display the product
using any file name given in RADFIL.

If you still have trouble, send me a sample of your files and the file
name/directory structure you are using and I'll see what I can see.

Steve Chiswell
Unidata User Support

On Wed, 26 Oct 2005, Arthur A. Person wrote:

> Steve,
>
> On Wed, 26 Oct 2005, Steve Chiswell wrote:
>
> > Art,
> >
> > We don't do any formatting to the Level II files you can
> > obtain via the IDD. The BZIP2 block compression is specified by the
> > ROC ICD and done at the source.
> >
> > Note that some files which you obtain via the web are compressed as
> > files (or tarfiles), and this is not the same as files which employ
> > data compression within them. If you obtained tarfiles or gzipped/bzip2
> > compressed files for download, then these need to be unpacked and/or
> > uncompressed. If you do an "od -c" on the file, you should see that
> > the first 9 bytes are ARCHIVE2. or AR20001. If not, then thats not a
> > valid format.
>
> I'm using .Z compressed files from NCDC.  I uncompress them and they have
> headers that look like:
>
> 0000000   A   R   2   V   0   0   0   1   .   2   0   2  \0  \0   2 225
> 0000020  \0 003 304 330   K   P   B   Z  \0  \0  \0  \0  \0  \0  \0  \0
> 0000040  \0  \0  \0  \0 004 270  \0 017   u 334   2 225  \0 003 334   q
> 0000060  \0 016  \0 001   2 223 004 323 002 001 002 001 002 001 002 001
> 0000100 002 001 002 001 002 001 002 001 002 001 002 001 002 001 002 001
>      .
>      .
>      .
>
> When I put these in a directory where nmap2 can find them, it doesn't use
> them as data, whereas if I put files there collected by the LDM from the
> IDD, these work.  Should nmap2 be able to read these NCDC plain files?
> I'm using gempak version 5.8.3a.
>
> > The Unidata GEMPAK release does handle both the uncompressed as well as
> > bzip2 compressed Level II files. In fact, before I added the bzip2
> > capability within the GEMPAK routines, I provided dcnexr2 decoder to
> > uncompress the bzip2 to products into their uncompressed versions.
>
> I thought I remembered something like that... but since I can't make the
> plain files above work, I thought maybe something changed.
>
>                                   Thanks.
>
>                                     Art.
>
> > This
> > isn't needed now as the bzip2 routines are linked in. The dcnexr2
> > program did another thing however. It added the 4 character station ID
> > into bytes 21-24 of the ARCHIVE2.0 header since otherwise, those files
> > did not have any station location information (ID or lat/lon). If bytes
> > 21-24 are null/blank, then the files should use the supplied file naming
> > template convention for NEXRII in datatype.tbl so that the site ID can
> > be determined.
> >
> > The newer files which have the AR2V0001.0 header do have the station ID
> > in bytes 21-24
> >
> > Steve Chiswell
> > Unidata User Support
> >
> >
> >
> > On Wed, 2005-10-26 at 13:58, Arthur A. Person wrote:
> >> Hi...
> >>
> >> Does anyone have or know of a program to convert NCDC plain level II
> >> nexrad data into the Unidata formatted files?
> >>
> >> Also, does anyone know whether the gempak and/or nmap2 packages are
> >> supposed to be able to read the plain uncompressed NCDC nexrad II files,
> >> or do they only work with the Unidata formatted bzip2 compressed files?
> >> I tried the plain files with nmap2 but it didn't seem to recognize them.
> >>
> >>                            Thanks.
> >>
> >>                              Art.
> >>
> >> Arthur A. Person
> >> Research Assistant, System Administrator
> >> Penn State Department of Meteorology
> >> email:  address@hidden, phone:  814-863-1563
> >
> >
>
> Arthur A. Person
> Research Assistant, System Administrator
> Penn State Department of Meteorology
> email:  address@hidden, phone:  814-863-1563
>