gnuplot documentation

148 gnuplot 4.3 70 SET-SHOW
70.111 Zero
The zero value is the default threshold for values approaching 0.0.
Syntax:
set zero
show zero
gnuplot will not plot a point if its imaginary part is greater in magnitude than the zero threshold.
This threshold is also used in various other parts of gnuplot as a (crude) numerical-error threshold.
The default zero value is 1e-8. zero values larger than 1e-3 (the reciprocal of the number of pixels in a
typical bitmap display) should probably be avoided, but it is not unreasonable to set zero to 0.0.
70.112 Zeroaxis
The x axis may be drawn by set xzeroaxis and removed by unset xzeroaxis. Similar commands
behave similarly for the y, x2, y2, and z axes.
Syntax:
set {x|x2|y|y2|z}zeroaxis { {linestyle | ls }
| { linetype | lt }
{ linewidth | lw }}
unset {x|x2|y|y2|z}zeroaxis
show {x|y|z}zeroaxis
By default, these options are off. The selected zero axis is drawn with a line of type
and width (if supported by the terminal driver currently in use), or a user-defined style
.
If no linetype is specified, any zero axes selected will be drawn using the axis linetype (linetype 0).
set zeroaxis is equivalent to set xzeroaxis; set yzeroaxis. Note that the z-axis must be set separately
using set zzeroaxis.
Examples:
To simply have the y=0 axis drawn visibly:
set xzeroaxis
If you want a thick line in a different color or pattern, instead:
set xzeroaxis linetype 3 linewidth 2.5
70.113 Zlabel
This command sets the label for the z axis. Please see set xlabel (p. 141).
70.114 Zmtics
The set zmtics command changes tics on the z axis to months of the year. Please see set xmtics
(p. 142) for details.
70.115 Zrange
The set zrange command sets the range that will be displayed on the z axis. The zrange is used only
by splot and is ignored by plot. Please see set xrange (p. 142) for details.