The acoustics backscattering data on CD#2 and CD#3 may be displayed using Matlab® routines. Matlab® is a product of The MathWorks, Inc. and may be purchased on-line from mathworks.com.
Here is a brief description of the procedures and mfiles used to make 3D "curtain" plots and 2D "data as a function of time or distance" plots of the acoustic backscattering data collected during the Workshop-at-Sea.
Included on this CD are a series of nested mfiles with the
You may download these files or use them directly from the CD:
Begin by unzipping the ascii data files (e.g. f017986/d930612/t202037d.gz).
Then load the data into the MATLAB® workspace.
Running curtain.m on the MATLAB® command line calls the other mfiles.
The setupplt.m mfile puts up a window that lets you change the file name and some other properties of the plot. You must put the filename in the place which asks for it. Loading the file alone will not tell the program which file to plot.
doplot.m does the work of plotting the data and it calls a couple of other files to assist with the color mapping. Doplot also turns on rotate3d, so that you can use your cursor to rotate the 3-D plot image.
The mfiles to fix the position data are no longer used by Doplot.
Normally the position data are fixed before running curtain.m.
The code for gpsfix.m is actually in doplot.m, but only as commented text now.
quitplot.m closes the menu window and clears the workspace of working matricies, but it does not clear the 3D figure.
The data format:
Curtain assumes the data to be plotted are in a format
that consists of a series of rows each with:
yearday_time, lat, lon, tran, mindepth, maxdepth, depthint,sv1,sv2,sv3....svn
In other words, each row has the data from one integration time interval with the first seven columns describing the data and columns eight to n with the sv data from each depth strata.
The column designated "tran" simply has the transducer frequency in it i.e. 120 for 120 kHz.
Another set of mfiles is present which enables the 2D plotting of the acoustics data as a function of time or distance.
The two files:
When run on the MATLAB® command line, callplot.m puts up a figure window and then presents input lines to specify needed inputs to make the plot, i.e.
Following the automatic placement of the figure legend, use the cursor to first place the y-axis label [Depth (meters)] and then the x-axis label [Time (Yearday) or Distance (meters)].