mb7k2ss
Section:  MB-System 5.0  (1)
Updated:  3 June 2013 
Index


 
NAME

mb7k2ss - extracts sidescan sonar
data from Reson 7k format data, bins and lays the sidescan
onto the seafloor, and outputs files in the MBF_MBLDEOIH
formst (MBIO format id 71).

 
VERSION

Version 5.0

 
SYNOPSIS

mb7k2ss [-Atype
-Bbottompickmode/bottompickthreshold -C -Dinterpbins
-Fformat -Ifile -Lstartline/lineroot
-M -Ooutfile -Qroutetimefile -Rroutefile
-Ttopogridfile -Urangethreshold -X -H -V]

 
DESCRIPTION

mb7k2ss is a utility that extracts Edgetech sidescan data from
Reson 7k format (MBIO format 88) data and outputs in the MBF_MBLDEOIH
format (MBIO format 71). Edgetech sonar systems may include dual
frequency sidescans and a subbottom profiler. Users may use the -A
option to specify whether low frequency or high frequency sidescan data
are extracted. By default, low frequency sidescan is extracted.
MB7k2ss can operate on a single input file or on a datalist
referencing many input files.

The raw sidescan consists of port and starboard channels, each with
thousands of samples ordered uniformly in time from the sonar ping.
MB7k2ss outputs a lower resolution single sidescan swath laid
out onto the seafloor and ordered in pixels with uniform spacing in
acrosstrack distance. Typically the output swath will have 4001
sidescan pixels, each representing an average of several raw samples.
To achieve this result, the program calculates the location
of each raw sample, and bins the samples into the output swath.
By default, the program uses the sonar altitude and a flat bottom
assumption to calculate the sample positions. If a topography grid
covering the survey area is input using the -T option, then
the sample positions will be calculated using that topography and
the resulting sidescan will be properly located on the seafloor
(that is, if the topography is accurate...).

The method used to determine the sonar altitude is controlled using the
-B option. By default, the program will use the altitude value
recorded in the vehicle navigation records. Users may also specify use
of nadir bathymetry from co-recorded multibeam bathymetry, or the
altitude can be picked from the first arrival observed in the sidescan
data itself.

The extracted sidescan data file(s) can be organized three ways.By
default there will be a separate output file for every input file.
If the -O option is used to specify a single output file, then
all of the specified sidescan data will be output to that file. If
the -Q or -R option is used to specify a survey route file
that includes the waypoints covered while collecting the data file(s)
referenced by -Ifile, then the output sidescan data will
be broken up by the sequential lines defined by the waypoints. The
-R option requires a route file of the form exported by MBgrdviz.
The -Q option requires a route file that includes the time
at which each waypoint is reached in the data; this can be generated
from a regular route file using mbroutetime. In either of these
cases each output file will be named using the  line root name
specified by -Lstartline/lineroot with a sequential line
number starting from startline. All output files will have a
".mb71" suffix.

The program mbextractsegy is available to extract subbottom profiler
data from Reson 7k data.

 
AUTHORSHIP

David W. Caress (caress@mbari.org)




  Monterey Bay Aquarium Research Institute



Dale N. Chayes (dale@ldeo.columbia.edu)




  Lamont-Doherty Earth Observatory

 
OPTIONS


-A


mode



This option sets the types of data to be extracted and output.
If -A1 is given, then any low frequency sidescan
in the input will be extracted to the output. If -A2
is given, then any high frequency sidescan records are extracted.
Default: Low frequency sidescan records are extracted.
-B


bottompickmode/bottompickthreshold



This option sets the source of the sonar first arrival time used for
laying out sidescan on the seafloor. If bottompickmode = 1,
then mb7k2ss will use the altitude value associated with
platform navigation. If bottompickmode = 2, then mb7k2ss
will extract the first arrival time from multibeam bathymetry in the
7k data stream. If bottompickmode = 3, then mb7k2ss
will pick the first arrival time in the sidescan sonar data by looking
for the first sample with an amplitude > bottompickthreshold times the
maximum amplitude in the trace. The altitude used will be the average of
the first arrival times calculated for the port and starboard channels.
Default: fIbottompickmode = 1.
-C





This option causes  mb7k2ss to print out any comment records
encountered in the input Reson 7k data.
-D


interpbins



Causes interpolation over gaps in the output sidescan resulting from draping
the sidescan on topography. The interpbins values sets the maximum
gap size over which interpolation will be applied.
-F


format



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 Reson 7k format data files (MBIO
format 88).
-H


This "help" flag cause the program to print out a description
of its operation and then exit immediately.
-I


infile



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 88


        datafile2 88




This program only reads Reson 7k format data files (MBIO
format 88).
-L


startline/lineroot



This option sets the starting line number and the output filename root
used when -R is specified so that data are output according
to planned survey lines. Default: startline = 1; lineroot = "jstar".
-M





This option causes mb7k2ss to omit data during turns when
extracting into line files according to a specified set of waypoints
(-R option). The traces will not be output until the heading is
within 15 degrees of the next survey line's bearing.
-O





This option sets the output MBF_LDEOIH (MBIO format 71) format file path.
If -O is not invoked, the output filename (or filenames if a datalist
is being processed) will be the input swath filename with the ".s7k" or ".mb88"
suffix replaced by a ".mb71) suffix. The record types to be extracted are set
using the -A option.
-Q


routetimefile



This option specifies a file containing the times that the survey reached
the intended waypoints. This text file consists of lines of the form:

        count waypoint longitude latitude heading time_d




where count is just an integer counter starting at 0, waypoint is the waypoint
number starting at 0, longitude and latitude are the waypoint position in
decimal degrees, heading is the heading in decimal degrees, and time_d is
the unix or epoch time (time since 00:00:00 January 1, 1970) in decimal
seconds that the survey reached this waypoint. This file can be generated from
an mbgrdviz route file and survey data using the program mbroutetime.
If routetimefile is specified, mb7k2ss
will output data in files corresponding to the planned survey lines.
The output file names will be based on lineroot and will include
the line number starting with starline, both of which are specified
using the -L options.  If none of -O, -Q, or -R are
invoked, the output filename (or files if a datalist is being processed) will
be the input swath filename with an ".mb71" suffix appended.
-R


routefile



This option specifies an mbgrdviz route file containing the intended
waypoints of the survey. If routefile is specified, mb7k2ss
will output sidescan data in files corresponding to the planned survey lines.
The output file names will be based on lineroot and will include
the line number starting with starline, both of which are specified
using the -L options.  If none of -O, -Q, or -R are
invoked, the output filename (or files if a datalist is being processed) will
be the input swath filename with an ".mb71" suffix appended.
-T


topogridfile



This option specifies a GMT grid file containing a topography model of the
survey area. When available, mb7k2ss, uses the topography to calculate
the position of each raw sidescan sample on the seafloor prior to binning
the sample into the swath data. This method is considerable improvement over the
flat bottom assumption used when topography is unavailable. The grid file
must contain topography (positive up) rather than bathymetry (positive down).
-U


rangethreshold



If the -R option is specified, mb7k2ss breaks up the
output into files corresponding to survey lines specified in a route file.
This option sets the threshold distance in meters used to determine when
a waypoint along the route has been reached; the program considers the
next waypoint reached when the range to the waypoint becomes smaller
than rangethreshold and then ceases to decrease.
Default: rangethreshold = 50 m.
-V


This option increases the verbosity of mb7k2ss, causing it
to print out messages regarding its progress to stdout.
-W


swathwidth
This option sets the output sidescan swath width in meters. By default
mb7k2ss calculates the swath width to use all of the samples available
in the original data.
-X


This option switches port and starboard sidescan channels.


 
EXAMPLES

Suppose that we have collected two Reson 7k datafiles incorporating
multibeam sonar data, sidescan data, and subbottom profiler data, and
that the filenames are:

        20070809_173212.s7k

        20070809_175133.s7k
After running mb7kpreprocess on these files to fix issues and
prepare the data for processing, we will have two additional files named:

        20070809_173212.mb88

        20070809_175133.mb88
After editing the bathymetry in the ".mb88" files with mbedit,
and running mbprocess to apply the edits, we will have two processed
files that are, among other uses, suitable for sidescan extraction:

        20070809_173212p.mb88

        20070809_175133p.mb88
If we have two datalist files, one called datalist.mb-1 referencing the ".mb88"
files with the following contents:

        20070809_173212p.mb88 88

        20070809_175133p.mb88 88
and another called datalistp.mb-1 referencing the first datalist with a
$PROCESSED tag:

        $PROCESSED

        datalist.mb-1 -1
then we can extract the Edgetech sidescan from the processed files using:

        mb7k2ss -v -A1 -B2 -I datalistp.mb-1 \

                -M -X -R MAUV_Axial_1v4.rte -L1/Axial07SS \


                -T AxialCalderaMBARIAllTopo.grd

Here the -R option specifies an MBgrdviz route file that was
followed in collecting the data. By using this option, the output sidescan
files will be broken into lines defined by the route waypoints, and the
output filenames will be sequentially numbered. The -T option specifies a
topography grid that is used by mb7k2ss to lay out the sidescan on
the seafloor. The output appears as follows:

        Program mb7k2ss

        Version $Id: mb7k2ss.1 2096 2013-06-04 08:17:22Z caress $


        MB-system Version 5.1.1beta5



        Data records to extract:


             Low Sidescan


             Sidescan port and starboard exchanged



        Imported 45 waypoints from route file: MAUV_Axial_1v4.rte


        Grid read:


          Dimensions: 2072 3558


          Geographic Coordinate System Name: Geographic WGS84


          Geographic Coordinate System ID:   4326


          Longitude:  229.926767 230.060367  0.000065


          Latitude:   45.866667 46.026700  0.000045


          Internal Grid Projection Mode:         0


          Internal Grid Projection ID:           epsg4326


        Data Read:


          grid_projection_mode:     0


          grid_projection_id:       epsg4326


          nodatavalue:              -10000000.000000


          nx:                       2072


          ny:                       3558


          min:                      -2302.588135


          max:                      -1382.877319


          xmin:                     229.926767


          xmax:                     230.060367


          ymin:                     45.866667


          ymax:                     46.026700


          dx:                       0.000065


          dy:                       0.000045


          data:                     71467008



        Data records read from: 20070809_173212p.mb88


             Survey:        2330


             File Header:   2


             Bluefin CTD:   1152


             Bluefin Nav:   942


             Subbottom:     0


             Low Sidescan:  2328


             High Sidescan: 0



        Generating inf file for Axial07SS_0001_sslo.mb71


        Generating fnv file for Axial07SS_0001_sslo.mb71



        Data records written to: Axial07SS_0001_sslo.mb71


             Low Sidescan:  2759


             High Sidescan: 0



        Generating inf file for Axial07SS_0002_sslo.mb71


        Generating fnv file for Axial07SS_0002_sslo.mb71



        Data records written to: Axial07SS_0002_sslo.mb71


             Low Sidescan:  369


             High Sidescan: 0



        Data records read from: 20070809_175133p.mb88


             Survey:        2367


             File Header:   2


             Bluefin CTD:   1158


             Bluefin Nav:   942


             Subbottom:     0


             Low Sidescan:  2367


             High Sidescan: 0



        Generating inf file for Axial07SS_0003_sslo.mb71


        Generating fnv file for Axial07SS_0003_sslo.mb71



        Total data records read:


             Survey:        4697


             File Header:   4


             Bluefin CTD:   2310


             Bluefin Nav:   1884


             Subbottom:     0


             Low Sidescan:  4695


             High Sidescan: 0


         Total data records written:


              Low Sidescan:  4160


              High Sidescan: 0


 
SEE ALSO

mbsystem(1), mbformat(1), mbinfo(1), mb7kpreprocess(1),
mb7k2jstar(1), mbextractsegy(1), mbbackangle(1), mbprocess(1)

 
BUGS

No doubt.



 
Index

NAME

VERSION

SYNOPSIS

DESCRIPTION

AUTHORSHIP

OPTIONS

EXAMPLES

SEE ALSO

BUGS

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