The entries in the format dialog are all straightforward to use except the “X Ticks” and “Y Ticks” entries. These are used to specify how the axes are labeled. The tick marks for the axes are usually computed automatically from the ranges of the data. Every attempt is made to choose reasonable positions for the tick marks regardless of the data ranges (powers of ten multiplied by 1, 2, or 5 are used). To change what tick marks are included and how they are labeled, enter into the “X Ticks” or “Y Ticks” entry boxes a string of the following form:
label position, label position,
...
A label is a string that must be surrounded by quotation marks if it contains any spaces. A position is a number giving the location of the tick mark along the axis. For example, a horizontal axis for a frequency domain plot might have tick marks as follows:
XTicks: -PI -3.14159, -PI/2
-1.570795, 0 0, PI/2 1.570795, PI 3.14159
Tick marks could also denote years, months, days of the week, etc.
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