[IGSMAIL-1525] RINEX compression tools

[Yuki]

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IGS Electronic Mail      Mon Jan 20  4:26:19 PST 1997      Message Number 1525
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Author: Yuki Hatanaka
Subject: RINEX compression tools

Dear colleagues,

At the IGS Analysis Center Workshop at NOAA in March, 1996, it was 
recommended that a new RINEX compression procedure proposed by Yuki 
Hatanaka (GSI) should be prepared for extensive tests by the IGS 
community. After a certain test period the IGS Governing Board 
should then decide if this compression scheme will be adopted as a 
new standard for RINEX observation file distribution.

After the workshop, Yuki Hatanaka and Werner Gurtner have again 
looked into the programs, refined the source code, added some more 
useful functions, and checked them on UNIX, MS-DOS, and VMS systems. 
Now the programs are ready for distribution for an extensive test. 

Following are the features of the programs:

  - The compression is done in two steps:

    1)  RINEX observation file --> Compact RINEX observation file
        (new compression algorithm, ASCII-->ASCII)

    2)  Compact RINEX observation file --> compressed file
        (standard UNIX .Z-compression)

    (RINEX navigation and meteorological files are continued to be 
     compressed with the UNIX .Z-compression only.)

* - The total compression rate is about 8 (compared to about 2.9     *
*   for the .Z-compression alone) for the case of 30s sampling data, *
*   and more for shorter sampling (e.g. about 10 for 1s).            *

  - Compatible to RINEX II observation files 

  - Free from rounding errors

  - Useful front-end command (script) files have been added for the 
    processing of multiple files and for the combination of the 
    two-step compression/decompression into one command. The same 
    commands also handle the pure .Z-compression/decompression of 
    other RINEX files.

The source files (written in ANSI C), binary executables (for several 
OS), command (script) files, sample data, and documents are available 
by anonymous ftp at the following addresses:

GSI:

   ftp://terras.gsi-mc.go.jp/pub/software/RNXCMP/

AIUB:

   Internet:   ubeclu.unibe.ch
   User:       anonymous
   Directory:  cd AIUB$FTP    (that's a hidden directory)
               cd RNXCMP      (do the change in these two steps!)

Please check readme.txt for instructions about compiling and usage.

The current version should be able to be compiled and run on UNIX, 
DOS, and VMS systems. So far, we have checked it on SunOS4.1.3
SunSolaris2.5, HP-UX9.05, MS-DOS, VMS VAX and Alpha system.

Bug reports, any technical feedbacks for further refinement and
standardization of the procedures as well as comments to the 
proposed new standard are welcome.

Yuki Hatanaka   (hata at gsi-mc.go.jp)
Werner Gurtner  (gurtner at aiub.unibe.ch)


[Mailed From: hata at gsi-mc.go.jp]