Gnuplot in Action, Second Edition

Appendix D. Palettes and false-color plots

Gnuplot provides a facility to map numeric values into a continuous range of colors. This allows you to create false-color plots (or heatmaps): graphs in which a numeric value is represented by a color, instead of by position.

In this appendix, we’ll first study how to set up such mappings between numbers and colors. Because the values in a false-color plot typically form a continuum, the mapping usually consists of a continuous color ramp or color gradient. The gnuplot command to create and manage such color gradients is set palette, and hence I’ll refer to these mappings as palettes. After introducing the commands to define palettes, we’ll look in detail at a catalog of example palettes for a variety ...