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Re: 20001129: test NIDS floater products

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  • Subject: Re: 20001129: test NIDS floater products
  • Date: Thu, 7 Dec 2000 14:27:22 -0700 (MST)
On Thu, 7 Dec 2000, Tom Yoksas wrote:

> >From:  Robb Kambic <address@hidden>
> >Organization:  UCAR/Unidata
> >Keywords:  200011291843.eATIhJp06962 IDD NIDZ floater
> 
> Robb,
> 
> Last week, you sent the following:
> 
> >I saved some of the floaters products on zero, ~ldm/data/radar.  These
> >products have 2 extras nulls at the end so they have different md5
> >checksums.
> >ie.
> >...
> >...
> >0102220 327 020   W 347 020   W 027  \0 310   l 233 372  \r  \r  \n 003
> >0102240  \0  \0   
> >
> >Hopefully your decoder can handle the extra chars.  Also are the file
> >names in a usable format?
> 
> First, the file names are fine.
> 
> Second, the products you saved do not appear to be the zlib-compressed
> NIDS products.
> 
> In support of the files not looking like the zlib-compressed images I
> note that the file sizes are exceedingly large:
> 
> % ls -alt *.N0RARX
> -rw-rw-r--   1 ldm      ustaff     24366 Nov 29 11:31 200011291829.N0RARX
> -rw-rw-r--   1 ldm      ustaff     28621 Nov 29 11:31 200011291730.N0RARX
> -rw-rw-r--   1 ldm      ustaff     28393 Nov 29 11:31 200011291740.N0RARX
> -rw-rw-r--   1 ldm      ustaff     27250 Nov 29 11:31 200011291750.N0RARX
> -rw-rw-r--   1 ldm      ustaff     26702 Nov 29 11:31 200011291800.N0RARX
> -rw-rw-r--   1 ldm      ustaff     26188 Nov 29 11:31 200011291810.N0RARX
> -rw-rw-r--   1 ldm      ustaff     25232 Nov 29 11:31 200011291819.N0RARX
> 
> Note that these files are all larger than about 25 KB.  I suspect that
> these files are probably the encrypted ones from the datastream, not
> the zlib-compressed ones.
> 
> Compare these sizes with a slew of zlib-compressed NIDS products:
> 
> % ls -alt *_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14359 Dec  7 05:03 200012071201_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14419 Dec  7 04:53 200012071151_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14557 Dec  7 04:43 200012071141_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14903 Dec  7 04:33 200012071132_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     15145 Dec  7 04:25 200012071122_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14645 Dec  7 04:14 200012071112_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14598 Dec  7 04:04 200012071102_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14938 Dec  7 03:54 200012071052_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     15190 Dec  7 03:44 200012071042_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     15245 Dec  7 03:34 200012071033_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     15046 Dec  7 03:24 200012071023_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14623 Dec  7 03:15 200012071013_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14605 Dec  7 03:05 200012071003_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14349 Dec  7 02:55 200012070953_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14354 Dec  7 02:45 200012070943_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14502 Dec  7 02:35 200012070934_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     13793 Dec  7 02:25 200012070924_N0RARX.nidz
> -rw-rw-r--   1 ldm      ustaff     14060 Dec  7 02:16 200012070914_N0RARX.nidz
> 
> The current file sizes are typically less than 15 KB AND the station in
> question (ARX, La Crosse, WI) is just now seeing some weather.  Back on
> Nov 29, the radar was continuously operating in clear air mode, so one
> could expect the file sizes to be smaller since there was less data to
> compress.
> 
> To test my server against altered zlib-compressed NIDS files, I did the
> following:
> 
> o copy a set of the *.nidz files to a separate directory
> o appended two-byte sequence to the end of each file (0x010a instead of 
> 0x0000)
> o ran my ADDE image list and get servers against those files
> 
> In this test, everything ran fine, so I feel confident that my servers
> will work on altered zlib-compressed NIDS products.
> 
> >The pqact entry:
> >
> ># save FLOATER
> >NMC3    ^FLOATER SDUS5. .... ([0-3][0-9])([0-2][0-9])([0-5][0-9])
> >/p(......)
> >        FILE    data/radar/(\1:yyyy)(\1:mm)\1\2\3.\4
> >#
> 
> Can you check to make sure that the files being redirected here are not
> the encrypted ones instead of the zlib-compressed ones?  It would be

Tom,

I only requested the files starting with nidz and then did the floater
conversion on them. They are in the ~ldm/data/radar dir on zero.  Yes the
size of the files is more in tune with what you expected. ie

-rw-rw-r--   1 ldm      ustaff     12675 Dec  7 14:07 200012072024.NCRARX
-rw-rw-r--   1 ldm      ustaff      9434 Dec  7 14:07 200012072034.N0RARX
-rw-rw-r--   1 ldm      ustaff      7407 Dec  7 14:07 200012072034.N0VARX
-rw-rw-r--   1 ldm      ustaff     11502 Dec  7 14:07 200012072034.NCRARX
-rw-rw-r--   1 ldm      ustaff      1315 Dec  7 14:07 200012072034.NTPARX
-rw-rw-r--   1 ldm      ustaff     11755 Dec  7 14:07 200012071954.N0RARX
-rw-rw-r--   1 ldm      ustaff      8889 Dec  7 14:07 200012071954.N0VARX
-rw-rw-r--   1 ldm      ustaff     12896 Dec  7 14:07 200012071954.NCRARX
-rw-rw-r--   1 ldm      ustaff      3516 Dec  7 14:07 200012071954.NTPARX
-rw-rw-r--   1 ldm      ustaff     10774 Dec  7 14:07 200012072004.N0RARX
-rw-rw-r--   1 ldm      ustaff      8496 Dec  7 14:07 200012072004.N0VARX
-rw-rw-r--   1 ldm      ustaff     12643 Dec  7 14:07 200012072014.NCRARX
-rw-rw-r--   1 ldm      ustaff      3521 Dec  7 14:07 200012072014.NTPARX
-rw-rw-r--   1 ldm      ustaff      9993 Dec  7 14:07 200012072024.N0RARX
-rw-rw-r--   1 ldm      ustaff      7916 Dec  7 14:07 200012072024.N0VARX
-rw-rw-r--   1 ldm      ustaff      3518 Dec  7 14:07 200012072024.NTPARX


Robb... 




> _very_ useful to me to clear up the discrepency with the test files you
> saved soon.  I am just about to announce the availability of my
> distribution to the McIDAS community, and I would rather not have to
> release patches to fix a potential problem after the official release.
> 
> Tom
> --
> +-----------------------------------------------------------------------------+
> * Tom Yoksas                                             UCAR Unidata Program 
> *
> * (303) 497-8642 (last resort)                                  P.O. Box 3000 
> *
> * address@hidden                                   Boulder, CO 80307 *
> * Unidata WWW Service                             
> http://www.unidata.ucar.edu/*
> +-----------------------------------------------------------------------------+
> 

===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================