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#8 in #rinex
1.5MB
170 lines
Hatanaka
RINEX
file compression and decompression tool.
This tool is based on the RINEX crate.
Yuki Hatanaka created a simple yet efficient method to compress
RINEX files, it's called CRINEX,
latest revision is CRINEX3
and is specified
here.
For more information on the actual compression algorithm, refer to the hatanaka section of the library.
Supported revisions
- CRINEX1
- CRINEX3
CRINEX2 was never released
CRINEX
RINEX Compression is an algorithm designed for Observation Data RINEX.
Getting started
Decompress a CRINEX
file with -d
hatanaka -d --filepath data/V1/wsra0010.21d
By default this would produce a data/V1/wsra0010.21o
RINEX file,
to respect naming conventions.
hatanaka -d --filepath data/V3/KUNZ00CZE.crx
By default this would produce a data/V3/KUNZ00CZE.rnx
RINEX file,
to respect naming conventions.
To change the default output file name, use the -o
flag :
hatanaka -d --filepath data/V1/wsra0010.21d -o /tmp/v1/output.rnx
hatanaka -d --filepath data/V3/KUNZ00CZE.crx -o /tmp/v3/output.rnx
--strict
flag for modern OBS Data
CRX2RNX
violates RINEX standard
when decompressing V > 2 (modern) RINEX Observation data,
because decompressed epochs are not contrainted to 80 characters.
By default and at the moment, this tool behaves like CRX2RNX
.
Next release will propose a flag to change that behavior and strictly follow RINEX specifications:
hatanaka -d -s --filepath data/V3/KUNZ00CZE.cnx
This flag has no impact when dealing with old RINEX files.
Epoch events
COMMENTS
are preserved through compression / decompression, as you would expect.
Just like CRX2RNX
, epochs with special events (flag > 2) are left untouched.
Therefore, explanations on these epochs events are preserved.
Compression algorithm & limitations
This tool uses an M=8 maximal compression order, which should be fine for all CRINEX ever produced,
considering they were probably produced by CRX2RNX
which hardcodes an M=5 limitation.
Unlike CRX2RNX
, this tool is not limited to an hardcoded M value,
you can increase the default value if you think higher
compression will be encountered in a given file:
hatanaka -d -M 8 --filepath data/V3/KUNZ00CZE.cnx
According to Y. Hatanaka's publication, optimum compression performances are obtained for a 4th order compression,
which is handled with default parameters.
Dependencies
~10MB
~197K SLoC