mbm_vrefcheck
Section:  MB-System 5.0  (l)
Updated:  4 January 2001 
Index


 
NAME

mbm_vrefcheck - Macro to generate plot of crosstrack seafloor slope
from a swath sonar file.  The noise in this time series largely reflects
noise in the vertical reference used by the sonar.

 
VERSION

Version 5.0

 
SYNOPSIS

mbm_vrefcheck -Fformat -Ifile [-Sscale -Xxaxis -Axmin -Bxmax]

 
DESCRIPTION

mbm_vrefcheck is a macro which generates a plot of high pass
filtered apparent crosstrack seafloor slope.  The noise in this signal
appears to be dominated by noise in the vertical reference data 
used by the sonar system.  The crosstrack slopes are obtained by running
mblist. The resulting time series is filtered using the GMT
utility filter1d, which uses a time domain median filter with
a time width of 5 minutes.  The filtered signal contains little of
the actual bathymetric signal, and thus represents a combination of
noise in the seafloor reflection travel times and the vertical 
reference data stream.  Close inspection of Hydrosweep data collected 
on the R/V Ewing with an interactive editor (mbedit) reveals
clear variability in the observed crosstrack slope, even when
surveying essentially flat seafloor.  This suggests that the filtered
signal is probably dominated by vertical reference noise on the Ewing.
The plot is automatically rasterized and sent to a Novajet plotter
(assuming one is on the R/V Ewing).

 
AUTHORSHIP

David W. Caress (caress@mbari.org)




  Monterey Bay Aquarium Research Institute



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




  Lamont-Doherty Earth Observatory



Suzanne H. O'Hara (sohara@ldeo.columbia.edu)




  Lamont-Doherty Earth Observatory

 
OPTIONS


-A


xmin



Sets the start time of the plot in hours from the beginning of the
input file. If not specified, the beginning of the input file
will be used as xmin.
-B


xmax



Sets the end time of the plot in hours from the beginning of the
input file. If not specified, the end of the input file
will be used as xmax.
-F


format



Sets the format for the input swath sonar data using 
MBIO integer format identifiers. 
This macro 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 = 24.
-I


file



Data file from which the input data will be read.
-S


xscale



Sets the x-axis scale of the plot in inches/hour.  
Default: xscale = 1.2.
-X


xaxis



Sets the length of the x-axis in inches.  


 
EXAMPLES

Suppose one has obtained a Hydrosweep DS swath sonar data file 
called hs_ew9302_157_bcen.mb24 in the
L-DEO binary in-house format (format id 24). In order to generate a 
vertical reference noise plot:



       mbm_vrefcheck -F24 -Ihs_ew9302_157_bcen.mb24


 
SEE ALSO

mbsystem(l), mblist(l)

 
BUGS

This script is hard wired for the R/V Ewing installation. This will
have to be fixed for it to be useful elsewhere.







 
Index

NAME

VERSION

SYNOPSIS

DESCRIPTION

AUTHORSHIP

OPTIONS

EXAMPLES

SEE ALSO

BUGS

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