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A 3-D histogram

The program psxyz allows us to plot three-dimensional symbols, including columnar plots. As a simple demonstration, we will convert a gridded netCDF of bathymetry into an ASCII xyz table and use the height information to draw a 2-D histogram in a 3-D perspective view. Our gridded bathymetry file is called topo.grd and covers the region from 0 to 5 oE and 0 to 5 oN. Depth ranges from -5000 meter to sea-level. We produce the illustration by running this command:

    #!/bin/csh
    #        GMT EXAMPLE 08
    #
    #        @(#)job08.csh    1.8  07/01/99
    #
    # Purpose:    Make a 3-D bar plot
    # GMT progs:    grd2xyz, pstext, psxyz
    # Unix progs:    echo, rm
    #
    grd2xyz topo.grd >! $$
    psxyz $$ -B1/1/1000:"Topography (m)"::.ETOPO5:WSneZ+ -R-0.1/5.1/-0.1/5.1/-5000/0 \
       -P -JM5i -JZ6i -E200/30 -So0.0833333ub-5000 -U"Example 8 in Cookbook" -W0.25p -G240 -K >! \
       example_08.ps
    echo '0.1 4.9 24 0 1 9 This is the surface of cube' | pstext -R -JM -JZ -Z0 -E200/30 -O \
       >> example_08.ps
    \rm -f $$ .gmtcommands

The output can be viewed in Figure 6.8.

Figure 6.8: A 3-D histogram