Syntax: |
CONTOUR { x y } z nctr { min { incr }}
|
Qualifiers: |
|
Defaults: |
X=[1;2;3;…], y=[1;2;3;…],
|
Examples: |
CONTOUR X Y Z 10
|
The CONTOUR command draws contour lines for data contained in a regular matrix. If you instead have a scattered set of points contained in three vectors, first create a regular matrix from the data using the GRID command.
Suppose that z
is a matrix which has n columns and m
rows. The vectors x
and y
are optional, and if entered, are used for scaling the axes. Each matrix element,
z[i,j]
, is associated with the coordinates
(x[j],y[i])
.
The length of x
must be greater than or equal to n
and the length of y
must be greater than or equal
to m.
If x
and y
are not entered,
x
defaults to the set [1;2;3;...;n]
, and
y
defaults to the set [1;2;3;...;m]
, so that
matrix element z[i,j]
is
associated with the coordinates (j,i)
.
Polar coordinates
By default, the vectors x
and
y
are assumed to represent
Cartesian coordinates. If the \POLAR
qualifier is used, x
and
y
are assumed to represent polar
coordinates, with x
the radial
component and y
the angular component,
in degrees. The values are converted internally to rectangular coordinates,
and the vectors are returned unchanged.
Matrix boundary
By default, the boundary of the matrix is outlined within the axes. If this
boundary is not desired, use the
\-BORDER
qualifier.
Add more contours
To add more contours to an existing contour plot, re-issue the contour command
with the \CONTINUE
qualifier. If a legend
is being drawn, it will be continued from where it left off. You must have used the
\-RESET
qualifier on the previous
CONTOUR
command if you intend to
use \CONTINUE
on a
succeeding CONTOUR
command.
Contour level selection
Contour line properties
Legend
Axes
Examples