MB-System Unix Manual Page: mbps

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

    NAME

    mbps - Generates a PostScript perspective plot of a piece of swath sonar data.

    VERSION

    Version 5.0

    SYNOPSIS

    mbps [-Fformat -Ifilename -Nnpingsmax -Ppings
    -Aalpha -Byr/mo/da/hr/mn/sc
    -Dview_direction -Eyr/mo/da/hr/mn/sc -Ggap
    -Keta -Sspeedmin -T"title" -Xve
    -Wmeters_per_inch -Ydisplay_stats -Zdisplay_scales
    -V -H]

    DESCRIPTION

    mbps is a utility to generate an (almost correct) perspective view
    of a piece of swath sonar data. It is especially useful to get a detailed
    view of the quality of the data (which is not very well assessed in a contour
    plot) and to make pretty pictures of features that fit within a swath.
    The output is PostScript code, that can be piped to a PostScript printer, or to a file.
    The options are a bit hard to interpret without a picture. Consider a
    frame of reference tied to the ship, with z upward, x across the track
    (port being negative, starboard positive) and y along the track. Using
    the -D option, the data can be viewed from port, starboard,
    or from the back. In the first two cases, the y-axis is horizontal in
    the plot; in the third case, the x-axis is horizontal.  The angle alpha
    is the angle between the x-axis and the y-axis in the final view; eta is the angle of elevation of the observing point (90 degrees being the zenith).  The
    data points are plotted as triangular polygons with the vertices at three good (ie. unflagged) adjacent data points. A given point is adjacent to 8 points in the surrounding swath (top, bottom, 2 sides, and 4 corners).  Now that you are thoroughly
    confused, just try plotting a half-hour or so of data from your favorite
    place. The defaults are such that a decent plot should come out.
    The plot will be scaled automatically to fit on a page, and will contain vertical and horizontal scales, an arrow pointing in the direction of the ship's motion, coordinate axes, and miscellaneous
    information identifying the piece of data being plotted.
    Now change some of the options, and things should get clearer.

    AUTHORSHIP

    Russ T. Alexander

      Formerly at University of California at Santa Barbara

    Alberto Malinverno (now at Schlumberger)

      Lamont-Doherty Earth Observatory

    OPTIONS

    -A

    alpha

    Sets the angle alpha (degrees) between the y-axis (shiptrack direction) and
    the x-axis (across-track). Default = alpha = 70.
    -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

    view_direction

    Sets the viewing direction; viewdir is a single character, either
    P/p (view from the port side), S/s (starboard), or B/b (back). Default
    view_direction = S.
    -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 format for the input swath sonar data using
    MBIO integer format identifiers.
    This program uses the MBIO library and will read 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

    gap

    Sets the manner in which data gaps are displayed.  If gap = 1 then
    gaps are filled with black.  If gap = 0 then gaps are not filled and appear the same as the background color of the paper.
    Default: gap = 1.
    -H

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

    filename

    File from which the input data will be read. If
    no input file is specified, the input will be read
    from stdin. Default: filename = stdin.
    -K

    eta

    Sets the angle eta (degrees) that is the elevation of the observer over
    the plane defined by the mean depth. Default eta = 45.
    -N

    npingsmax

    Sets the maximum number of pings to be read and plotted.
    Default: npingsmax = 1000.
    -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).
    -S

    speedmin

    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 used. Default: speed = 0.
    -T

    "title"

    Sets the title printed at the top of the plot.  The title should be enclosed within double quotes.  Default: no title.
    -V

    If the -V flag is given, then mbps works in a "verbose" mode and
    outputs the program version being used and all read error status messages.
    -W

    meters_per_inch

    Sets the horizontal plotting scale.  Default: automatically calculates
    a scale such that the plot fits on a page.
    -X

    ve

    Sets the vertical exaggeration. Default ve = 5.
    -Y

    display_stats

    Sets whether the final plot includes info such as mean latitude, mean longitude, mean heading, alpha, eta, ve, scale, track length, begin time, and end time. if display_stats = 1 then the above info is plotted; if dispaly_stats = 0 then it is not plotted.  Default: display_stats  = 1.
    -Z

    display_scales

    Sets whether the final plot includes a horizontal scale, a vertical scale, an arrow pointing in the ship heading direction, and coordinate axes.  if display_scales = 1 then the above info is plotted; if dispaly_scales = 0 then it is not plotted.  Default: display_scales  = 1.

    EXAMPLES

    Suppose one wishes to take a look at data from a Hydrosweep file in
    L-DGO edmb format (data.edmb), starting at 09:00 and ending at
    10:30 on September 3, 1991. The following will output PostScript to a file called fred.

            mbps -F22 -Idata.edmb -B1991/9/3/9/0/0 -E1991/9/3/10/30/0 > fred

    SEE ALSO

    mbsystem(l), mbcontour(l), mbswath(l)

    BUGS

    mbps assumes that the ship was moving on a straight line. Weird
    plots will result if this is not the case.  mbps only draws polygons bewteen 3 adjacent good points; if isolated points without 2 neighbors exist they will not be apparent in the final plot.  The filling of bad polygons is not perfect and gaps in the black fill, especially at the edges of swaths, may occur.

     Index

    NAME
    VERSION
    SYNOPSIS
    DESCRIPTION
    AUTHORSHIP
    OPTIONS
    EXAMPLES
    SEE ALSO
    BUGS

Last Updated: 26 October 2009

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