Chapter 7. Decorations: labels, arrows, and explanations
This chapter covers
- Understanding layers and locations on a graph
- Adding arrows, labels, and other decorations
- Providing explanations using a key
- Changing a graph’s overall appearance
Data alone doesn’t tell a story. To be useful, the data needs to be placed in context: you must tell the observer what the data is (such as position versus time, particle count versus scattering angle, stock price versus date, and so on) and what units the data is plotted in (centimeters or inches, seconds or minutes, dollars or Euros). No plot is complete without this information.
But you can do much more to make a graph useful and informative: you can add arrows and annotations on the graph to point out and explain interesting features. You may also want to provide special tic marks and labels to make quantitative information stand out more. Or you can change the size and shape of the entire graph to accommodate a specific data set.
In this chapter, we’ll discuss all the means that gnuplot offers to put ancillary information on a plot (in addition to the data). Because much of this material is quite dry, I’ve gathered the most important commands and options together in the next section. Unless you have specific requirements, this may be all you need to know right now—gnuplot is good at automatically doing the right thing in most situations.