6.8 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 $^{o}$E and 0 to 5 $^{o}$N. Depth ranges from -5000 meter to sea-level. We produce the illustration by running this command:

grd2xyz guinea_bay.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