Chapter 9. Color, style, and appearance

This chapter covers

  • Global appearance options
  • Color
  • Lines and points
  • Size and aspect ratio

Whereas the previous few chapters dealt with very local aspects of a graph (such as an individual curve, a single text label, or the details of tic mark formatting), the present chapter addresses global issues. We begin with a long and important section on color. Color is an exciting topic, and it opens a range of options for data visualization; I’ll explain gnuplot’s support for color handling in detail.

Next, we discuss a few details that matter if you want to modify the default appearance of point types, dash patterns, and the automatic selection of visual styles. The overall size and aspect ratio of the graph are the subjects of the closing section of this chapter.

9.1. Color

Color is an important element in visualization. At the base level, colors are often easier to distinguish than dash patterns or different symbol shapes. But colors open many more options for visualization—in fact, colors by themselves are sufficient to represent semantic information (we’ll come back to this in appendix D). And finally, color is just plain fun!

9.2. Lines and points

9.3. Customizing color, dash, and point sequences

9.4. Global styles

9.5. Overall appearance: aspect ratio and borders

9.6. Summary