MB-System Unix Manual Page
Section: MB-System 5.0 (1)
Updated: 26 March 2014
mbswplspreprocess - prepairs a SWATHplus sonar file (MBIO
format 222) for processed with MB System.
mbswplspreprocess [-ABGNRSHV] [-Fformat]
[-Jproj4command] [-Ooutfile] -Ifile
mbswplspreprocess prepairs a SWATHplus SXP (MBIO format 222)
file for processing with MB System.
MB System can read and plot SXP files
without modification. However, many of the editing and calibration programs
work best if each transducer channel is stored in a separate file (use
the -S option). In particular, multiple transducer channels pinging
simultaneously will trip up time filtering, since each channel in the
ping series has the same time stamp.
If during data acquisition using the SEA SWATH Real-Time Acquisition System
(SEA Swath Processor), the "Store All Data" option was selected in combination
with the "Downsample" Bathy filter, the SXP ping records will contain
both the original data (all samples rejected) and the filtered data (all
samples accepted) simultaneously. This will confuse most programs in MB
System. Use the -B and -R options as needed to strip out
the undesired set prior to processing.
SXP ping records contain both a raw amplitude and a processed amplitude
value for each sample. MB System reads and writes ONLY the processed amplitude
values, leaving the raw values untouched. Use the -A option to
copy (or restore) the raw amplitude values into the processed amplitude
slots so that they can be accessed by MB System.
David P. Finlayson (firstname.lastname@example.org)
Pacific Coastal and Marine Science Center, USGS
This option causes the program to copy the raw amplitude values stored
with each sample into the corresponding processed amplitude slot where
it can then be used by MB System.
This option causes the program to reverse the sample flag setting. That
is, rejected samples become accepted samples and vis-a-vis. This option
is always applied before option -R.
Sets the data format used if the input is read from stdin or from a file.
If format < 0, then the input file specified with the -I
option will actually contain a list of input swath sonar data files. This
program only reads Bathyswath (SWATHplus) format data files (MBIO
Print to stdout an ASCII representation of each data record read from the file.
This "help" flag cause the program to print out a description
of its operation and then exit immediately.
Sets the input file path. If format > 0 (set with the
-f option or mbdefaults) then the swath sonar data contained in infile
is read and processed. If format < 0, then infile
is assumed to be an ascii file containing a list of the input swath sonar
data files to be processed and their formats. The program will read
the data in each one of these files.
In the infile file, each
data file should be followed by a data format identifier, e.g.:
datafile1 222 1
datafile2 222 1
This program only reads SWATHplus format data files (MBIO format
The SWATHplus software packages operate with navigation in a user-defined
projected coordinate system. Resultantly, SXP format files contain
positions in a projected coordinate system rather than longitude and
latitude in geographic coordinates. Generally, the SXP files do not contain
any description of the projection used to obtain the eastings and northings
in those files. This option allows a user to specifiy the projection used
to translate the eastings and northings back into longitude and latitude.
If this option is not specified, MB-System will assume the data are
associated with UTM zone 1 north. The projection identifier must conform to
the same usage as with projections specified for mbgrid. For
instance, to fully specify a particular northern UTM zone, set projection =
UTMXXN where XX gives the UTM zone (defined from 01 to 60). As an example,
a northern UTM zone 12 projection can be specified using -JUTM12N. Southern
UTM zones are specified as UTMXXS. The European Petroleum Survey Group
(EPSG) has defined a large number of PCS's used worldwide and assigned
number id's to each; one can also specify the northern UTM zone 12
projection using its EPSG designation, or -Jepsg32612. The complete list of
projected coordinate systems supported by MB-System is given in the mbgrid
Do not write output file. Useful for inspecting files, especially combined
This option causes mbswplspreprocess to output all data to a single file
specified as outfile. By default, the program creates output files for
each input file. If combined with -S, this will serve as the basename
for a set of output files, one for each transducer.
This option removes all rejected samples from pings before writing output.
This option saves each transducer channel into a separate output file. This is
the best way to handle simultaneous pinging in MB System and the only way to
handle 3 or more transducer channel systems. The transducer channel will
be appended to the output filename as follows:
Suppose that one has collected a SWATHplus datafile incorporating interferometric
sonar data from a 2-transducer system pinging simultaneously. The file name
To split each transducer into its own file for better filtering support
from MB System, to reset the amplitude values to their original pre-processed
values, and to strip out any previously flagged data run:
- mbswplspreprocess -SAR -I20140418_150155.sxp
To export the data records stored in an SXP file to a text file:
- mbswplspreprocess -GN -I20140418_150155.sxp > output.txt
The SXP file format does not contain sufficient information to completely re-process
the data in MB System itself. For example, you should not attempt to re-calculate
bathymetry based on new sound velocity information. Ridged translations and
rotations are OK (static shifts in x, y, or z, rotations about the transducer reference point)
provided that each transducer channel resides in its own file (see the -S option). It is
always safe to edit and filter the soundings in mbedit and mbeditviz.
SXP files use a projected coordinate system for all transducer and sea
floor sample coordinates. The user must supply a .PRJ file defining the
coordinate system (usually UTM) for each input file before proceeding
with further processing in MB System. The coordinate system is not stored
in the SXP file data itself.
mbsystem(1), mbformat(1), mbinfo(1)
- SEE ALSO
Last Updated: 26 March 2014
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