gnuplot documentation

70 SET-SHOW gnuplot 4.3 105
Bit 2 for the diagonals that split each cell of the original grid into two triangles. The default pattern is
3, making all horizontal and vertical lines visible, but not the diagonals. You may want to choose 7 to
see those diagonals as well.
The undefined option lets you decide what the algorithm is to do with data points that are
undefined (missing data, or undefined function values), or exceed the given x-, y- or z-ranges. Such points
can either be plotted nevertheless, or taken out of the input data set. All surface elements touching a
point that is taken out will be taken out as well, thus creating a hole in the surface. If = 3,
equivalent to option noundefined, no points will be thrown away at all. This may produce all kinds of
problems elsewhere, so you should avoid this. = 2 will throw away undefined points, but keep
the out-of-range ones. = 1, the default, will get rid of out-of-range points as well.
By specifying noaltdiagonal, you can override the default handling of a special case can occur if
undefined is active (i.e. is not 3). Each cell of the grid-structured input surface will be divided
in two triangles along one of its diagonals. Normally, all these diagonals have the same orientation relative
to the grid. If exactly one of the four cell corners is excluded by the undefined handler, and this is
on the usual diagonal, both triangles will be excluded. However if the default setting of altdiagonal
is active, the other diagonal will be chosen for this cell instead, minimizing the size of the hole in the
surface.
The bentover option controls what happens to another special case, this time in conjunction with the
trianglepattern. For rather crumply surfaces, it can happen that the two triangles a surface cell is
divided into are seen from opposite sides (i.e. the original quadrangle is ’bent over’), as illustrated in
the following ASCII art:
C----B
original quadrangle: A--B displayed quadrangle: |\ |
("set view 0,0") | /| ("set view 75,75" perhaps) | \ |
|/ | | \ |
C--D | \|
A D
If the diagonal edges of the surface cells aren’t generally made visible by bit 2 of the there,
the edge CB above wouldn’t be drawn at all, normally, making the resulting display hard to understand.
Therefore, the default option of bentover will turn it visible in this case. If you don’t want that, you
may choose nobentover instead. See also
and
hidden line removal demo (hidden.dem)
complex hidden line demo (singulr.dem).
70.26 Historysize
Note: the command set historysize is only available when gnuplot has been configured with the GNU
readline.
Syntax:
set historysize
unset historysize
When leaving gnuplot, the value of historysize is used for truncating the history to at most that much
lines. The default is 500. unset historysize will disable history truncation and thus allow an infinite
number of lines to be written to the history file.
70.27 Isosamples
The isoline density (grid) for plotting functions as surfaces may be changed by the set isosamples
command.
Syntax: