The command "makecpt" has many options.
Many options make us happy, as well as confused because it is difficult
to know what we should use table.
Here are samples of CPT. I made GMT geographic maps by using various
colour palette tables, namely cool, copper, gebco, gray, haxby, hot, jet,
no_green, ocean, polar, rainbow, relief, sealand, seis, split, topo,
wysiwyg and blu2green. The table blu2green is my original and similar to
red2green but replaced red by blue. This table is defined by
Users who want to use blu2green table should copy GMT_blu2green.cpt to
% cp GMT_blu2green.cpt $GMTHOME/share/