A number of useful symbols are automatically defined whenever Ferret sets up a plot. Following any plotting command issue the command SHOW SYMBOLS/ALL to see a list. These plot symbols are listed and described in Chapter 6. Additional symbols are also listed at the end of this chapter. For example, if we wish to place a label "hello" at the upper right corner of a plot we might do the following
yes? PLOT/I=1:100 SIN(I/6) yes? LABEL/NOUSER ($ppl$xlen) ($ppl$ylen) 1 0 .2 hello
This labeling procedure would work regardless of the aspect ratio of the plot. Use the command SHOW SYMBOL/ALL to see the symbols (and see "General Global Symbols" in the PLOT+ Users Guide).
When used together with Ferret embedded expressions,symbols can be used to perform arithmetic on the plot geometry. For example, this command will locate the plot title in bold at the center of a plot regardless of the aspect ratio: