gnuplot documentation

70 SET-SHOW gnuplot 4.3 93
If the command set cntrparam is given without any arguments specified, the defaults are used: linear,
5 points, order 4, 5 auto levels.
Examples:
set cntrparam bspline
set cntrparam points 7
set cntrparam order 10
To select levels automatically, 5 if the level increment criteria are met:
set cntrparam levels auto 5
To specify discrete levels at .1, .37, and .9:
set cntrparam levels discrete .1,1/exp(1),.9
To specify levels from 0 to 4 with increment 1:
set cntrparam levels incremental 0,1,4
To set the number of levels to 10 (changing an incremental end or possibly the number of auto levels):
set cntrparam levels 10
To set the start and increment while retaining the number of levels:
set cntrparam levels incremental 100,50
See also set contour (p. 94) for control of where the contours are drawn, and set clabel (p. 91) for
control of the format of the contour labels and linetypes.
See also
and
contours demo (contours.dem)
contours with user defined levels demo (discrete.dem).
70.11 Color box
The color scheme, i.e. the gradient of the smooth color with min z and max z values of pm3d’s palette,
is drawn in a color box unless unset colorbox.
set colorbox
set colorbox {
{ vertical | horizontal }
{ default | user }
{ origin x, y }
{ size x, y }
{ noborder | bdefault | border [line style] }
}
show colorbox
unset colorbox
Colorbox position can be default or user. If the latter is specified the values as given with the origin
and size subcommands are used.
vertical and horizontal switches the orientation of the color gradient.
origin x, y and size x, y are used only in combination with the user option. The x and y values are
interpreted as screen coordinates by default, and this is the only legal option for 3D plots. 2D plots,
including splot with set view map, allow any coordinate system to be specified. Try for example:
set colorbox horiz user origin .1,.02 size .8,.04
which will draw a horizontal gradient somewhere at the bottom of the graph.
border turns the border on (this is the default). noborder turns the border off. If an positive integer
argument is given after border, it is used as a line style tag which is used for drawing the border, e.g.: