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7.8 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 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 Figure 7.8 by running this script:

    #!/bin/sh
    #               GMT EXAMPLE 08
    #
    # Purpose:      Make a 3-D bar plot
    # GMT progs:    grd2xyz, pstext, psxyz
    # Unix progs:   echo, rm
    #
    ps=example_08.ps
    grd2xyz guinea_bay.nc | psxyz -B1/1/1000:"Topography (m)"::.ETOPO5:WSneZ+ \
            -R-0.1/5.1/-0.1/5.1/-5000/0 -JM5i -JZ6i -E200/30 -So0.0833333ub-5000 -P \
            -U"Example 8 in Cookbook" -Wthinnest -Glightgray -K > $ps
    echo '0.1 4.9 24 0 1 TL This is the surface of cube' | pstext -R -J -JZ -Z0 -E200/30 -O >> $ps
    rm -f .gmt*

Figure 7.8: A 3-D histogram.

Next: 7.9 Plotting time-series along Up: 7. Creating GMT Graphics Previous: 7.7 A simple location Contents Index