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Re: CRAFT data hardware

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  • Subject: Re: CRAFT data hardware
  • Date: 05 May 2004 11:41:13 -0600
David,

IDV currently uses the uncompressed files (here at UPC, the ones that
dcnexr2 uncompresses).

Dcnexr2 for GEMPAk accomplishes 2 tasks:
1) uncompresses the data stream
2) adds the station ID to the data file header (eg the -s option) 
so that programs can determine where to plot the data based on the data,
rather than having to use the file name. This adds the station ID to
bytes 21-24 of the data header for the "ARCHIVE2." products, which is 
what is done in the build5.0 data with header "AR2V0001.


#2 above is needed for the pre-5.0 RDA build sites. Once all of the 
radar sites are upgraded to 5.0, this won't be necessary, and therefore
the added step of uncompressing with dcnexr2 would be superfluous.
Dcnexr2 is a bridge until build 5.0 is in place.

I will be adding the necessary uncompression to the GEMPAK routines,
but until all the sites are at build 5.0, the station ID will still have
to be provided either in the data header, or by the file template.

Steve Chiswell




On Wed, 2004-05-05 at 11:09, David Wojtowicz wrote:
> > Thanks.  GEMPAK doesn't have decompress built in so we would have to at
> > least decompress and keep about 12 hours or so on disk uncompressed.
> >
> 
> I think it'd be great if GEMPAK had the decompress built in.  Does IDV
> handle the compressed files?  The problem is the uncompressing does take up
> a huge amount of disk space, and is extremely CPU intensive,  so you're
> doing all this work on data, that you probably are only going to look at 1%
> of.
> 
> -----
> David Wojtowicz, Sr. Research Programmer, Sysadmin
> Dept of Atmospheric Sciences / Computer Services
> University of Illinois at Urbana-Champaign
> address@hidden  (217) 333-8390