Creating Plots of Ocean Depths

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Creating Plots of Ocean Depths

Once you have executed the shell script Etopo5, you can use bathmdl.gmt to create PostScript plots of the bathemetry data.

Examine the range of ocean depth values in bathmdl.gmt to create a custom color palette file.

An easy way to do this is to use the sort command. For example, give the command

sort -n +2 bathmdl.gmt > bathmdl.sort

then just look at the third value in the first row of bathmdl.sort to find the minimum value and the third value in the last row to find the maximum value.

Suppose you find that the range of depths in bathmdl.gmt (or bathmdl.sort) is 2000-5000; then the midpoint value is 3500. If you wish to create a color palette having six intervals with spacings of 500 per interval, you should give the command

makecpt -C500 -S6c -M3500 -Z > etopo5.cpt

(Be sure to name the output file etopo5.cpt.)

Edit the shell script PlotBath so that the values assigned to the w, e, s, and n variables are the west and east longitudes and south and north latitudes, respectively, of the boundaries of the geographic region that you specified in etopo5.par.

Modify the value assigned to the title variable in PlotBath to customize the figure's title to your liking.

Execute PlotBath.

This script creates a PostScript file etopo5.ps that is a plot of the ocean depths for this region. To construct the file, PlotBath:

Print PostScript file etopo5.ps or view with ghostview.

NOTE: In order to include the full title in the plot, it may be necessary for you to edit the PostScript file to increase the last value in the BoundingBox statement (second line of the etopo5.ps ).