MB-System Unix Manual Page: mbhistogram

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    mbhistogram
    Section:  MB-System 5.0  (1)
    Updated:  26 October 2009
    Index

    NAME

    mbhistogram - Generate a histogram of bathymetry, amplitude, or sidescan values
    from swath sonar data files.

    VERSION

    Version 5.0

    SYNOPSIS

    mbhistogram [-Akind -Byr/mo/da/hr/mn/sc
    -C -Dmin/max -Eyr/mo/da/hr/mn/sc
    -Fformat -G -Ifilename -Llonflip
    -Mnintervals -Nnbins -Pping
    -Rwest/east/south/north -Sspeed -V -H]

    DESCRIPTION

    mbhistogram reads a swath sonar data file and generates a histogram
    of the bathymetry,  amplitude,  or sidescan values. Alternatively,
    mbhistogram can output a list of values which break up the
    distribution into equal sized regions. These values can be
    used to construct a color table, producing an image which
    is histogram equalized. If desired, the histogram
    can be recast into a Gaussian distribution before output or
    the calculation of the histrogram equalization This feature
    is similar to the Gaussian option of grdhisteq. The linear
    histogram equalization is most appropriate for use with
    grayscale images, such as those produced from amplitude
    or sidescan data, and is used by the macro mbm_plot
    for that purpose. The Gaussian histogram equalization is
    well suited for shading of images, and is used by
    mbm_plot for shading of color bathymetry with
    amplitude data.
    The results are dumped to stdout.

    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

    kind

    Sets the kind of data to be processed, where

            kind = 0 : histogram of bathymetry data

            kind = 1 : histogram of beam amplitude data

            kind = 2 : histogram of sidescan data

    Default: kind = 2.
    -B

    yr/mo/da/hr/mn/sc

    This option sets the starting time for data allowed in the input data.
    The -E option sets the ending time for data. If the
    starting time is before the ending time, then any data
    with a time stamp before the starting time or after the
    ending time is ignored. If instead the starting time is
    after the ending time, then any data between the ending
    and starting time will be ignored. This scheme allows time
    windowing both inside and outside a specified interval.
    Default: yr/mo/da/hr/mn/sc = 1962/2/21/10/30/0.
    -D

    min/max

    Specifies the minimum and maximum data values used for
    constructing the histogram.
    The width of the bins is determined by (max - min)
    divided by nbins (see the -N option).
    The min value is the
    center of the first histogram bin, and the max value is the
    center of the last histogram bin.
    Data values falling outside the range of the bins are ignored.
    -E

    yr/mo/da/hr/mn/sc

    This option sets the ending time for data allowed in the input data.
    The -B option sets the starting time for data. If the
    starting time is before the ending time, then any data
    with a time stamp before the starting time or after the
    ending time is ignored. If instead the starting time is
    after the ending time, then any data between the ending
    and starting time will be ignored. This scheme allows time
    windowing both inside and outside a specified interval.
    Default: yr/mo/da/hr/mn/sc = 2062/2/21/10/30/0.
    -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 uses the MBIO library
    and will read or write any swath sonar
    format supported by MBIO. A list of the swath sonar data formats
    currently supported by MBIO and their identifier values
    is given in the MBIO manual page. Default: format = 11.
    -G

    This option causes the data histogram to be recast into a
    Gaussian distribution.
    -I

    filename

    Sets the input filename. If format > 0 (set with the
    -f option) 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 11

            datafile2 24

    This program uses the MBIO library and will read or write any swath sonar
    format supported by MBIO. A list of the swath sonar data formats
    currently supported by MBIO and their identifier values
    is given in the MBIO manual page. Default: infile = "stdin".
    -L

    lonflip

    Sets the range of the longitude values returned.
    If lonflip=-1 then the longitude values will be in
    the range from -360 to 0 degrees. If lonflip=0
    then the longitude values will be in
    the range from -180 to 180 degrees. If lonflip=1
    then the longitude values will be in
    the range from 0 to 360 degrees.
    Default: lonflip = 0.
    -M

    nintervals

    If nintervals > 0 then mbhistogram will
    calculate and output a list of values which break up
    the data distribution into equal sized regions.  This can
    be useful for constructing color tables which accentuate
    features in amplitude and sidescan data (the macro mbm_plot
    makes use of this feature). If this option is enabled, then the
    raw histogram is not output.
    -N

    nbins

    Sets the number of bins used to calculate the histogram.
    -P

    pings

    Sets the ping averaging of the input data. If pings = 1, then
    no ping averaging is performed. If pings > 0, then
    that number of input pings will be averaged to produce one output
    ping.  If pings = 0, then the ping averaging will automatically
    be done so that the along-track ping spacing is equal to the across-track
    beam spacing.
    Default: pings = 1 (no ping averaging).
    -R

    west/east/south/north

    Sets the longitude and latitude bounds within which swath sonar
    data will be read. Only the data which lies within these bounds will
    be read.
    Default: west=-360, east=360, south=-90, north=90.
    -S

    speed

    Sets the minimum speed in km/hr (5.5 kts ~ 10 km/hr) allowed in
    the input data; pings associated with a smaller ship speed will not be
    copied. Default: speed = 0.
    -T

    timegap

    Sets the maximum time gap in minutes between adjacent pings allowed before
    the data is considered to have a gap. Default: timegap = 1.
    -V

    Normally, mbhistogram only prints out the statistics obtained
    by reading all of the data.  If the
    -V flag is given, then MBCOPY works in a "verbose" mode and
    outputs the program version being used and all read error status messages.
    -H

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

    EXAMPLES

    Suppose one wishes to obtain a histogram of the sidescan data
    in a file called mbexample.mb41 containing raw data from a SeaBeam
    2112 sonar (format 41). The following will suffice:

     mbhistogram -F41 -I sb199411211212.rec -D0.0/45000 -N25

    to yield the following histogram:

     0.000000 183814

     1875.000000 30845

     3750.000000 5365

     5625.000000 1918

     7500.000000 951

     9375.000000 591

     11250.000000 403

     13125.000000 232

     15000.000000 189

     16875.000000 127

     18750.000000 108

     20625.000000 75

     22500.000000 85

     24375.000000 48

     26250.000000 30

     28125.000000 31

     30000.000000 28

     31875.000000 21

     33750.000000 10

     35625.000000 9

     37500.000000 4

     39375.000000 2

     41250.000000 2

     43125.000000 2

     45000.000000 1

    In order to obtain 16 values breaking up the distribution into
    equal sized regions, use the -M option:

     mbhistogram -F41 -I sb199411211212.rec -D0.0/45000 -N45000 -M25

    giving:

      -0.500011

     110.657221

     137.446811

     165.916284

     199.635469

     239.900007

     287.726270

     345.615610

     418.142114

     513.487776

     639.986551

     824.475879

     1140.372280

     1994.280032

     44803.495633

    SEE ALSO

    mbsystem(l), mbm_plot(l), grdhisteq(l)

    BUGS

    You find em, we fix 'em...

     Index

    NAME
    VERSION
    SYNOPSIS
    DESCRIPTION
    AUTHORSHIP
    OPTIONS
    EXAMPLES
    SEE ALSO
    BUGS

Last Updated: 26 October 2009

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