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 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 E and 0 to 5 N. Depth ranges from -5000 meter to sea-level. We produce the illustration by running this command:
#!/bin/csh # GMT EXAMPLE 08 # # $Id: job08.csh,v 1.5 2004/04/10 17:19:14 pwessel Exp $ # # Purpose: Make a 3-D bar plot # GMT progs: grd2xyz, pstext, psxyz # Unix progs: echo, rm # 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 -Glightgray -K >! \ example_08.ps echo '0.1 4.9 24 0 1 TL This is the surface of cube' | pstext -R -J -JZ -Z0 -E200/30 -O \ >> example_08.ps \rm -f $$ .gmt*
The output can be viewed in Figure 7.8.