Syntax: |
CONTOUR { x y } v nctr { min { incr }}
|
By default, the number of contours, nctr
, must be provided.
If nctr > 0
and the increment is
not specified, the actual number of contours drawn may not be the same as
the number that was asked for, since "nice" contour levels will be
selected and the range of values may not be neatly divisible by the
requested number. If the minimum is provided, but not the increment, a
"nice" value close to min
will be
used instead of the actual data minimum. If the minimum and the increment
are both specified, those exact values will be used for the contour
levels.
Specific contour levels
Specific contour levels can be requested by using the \SPECIFIC
qualifier. In this case, the vector lvls
should contain the desired contour levels.
Exact contour levels
Exact contour levels can be requested in three ways.
\SPECIFIC
qualifier and
enter a vector containing the desired levels.min
, and the contour level
increment, inc
. This produces a set of equally spaced contour levels,[min; min+inc; min+2*inc; ...; min+nctr*inc]
.nctr < 0
. This
produces a set of equally spaced contour levels, as above, using the actual
data minimum and the actual data maximum.Zooming in
When the minimum and maximum contour levels are to be determined, by default,
the entire range of the data is used. If the
\PARTIAL
qualifier is used, the minimum and maximum contour levels will be
determined by the region contained within the axes. Thus, to zoom in on a
particular region for more detail, pre-set the axis scales, using the
SCALES
command, before entering the CONTOUR
command. Of course, the \PARTIAL
qualifier does not apply when you request specific contour levels.