contour

Purpose

Contour plots.

Synopsis

contour(Z)
contour(Z,n)
contour(Z,v)
contour(x,y,Z)
contour(x,y,Z,n)
contour(x,y,Z,v)
C = contour(...)

Description

contour(Z) draws a contour plot of matrix Z. The contours are level lines in the units of array Z. The lower-left corner of the plot corresponds to Z(1,1). The number of contour lines and their values are chosen automatically by contour.

contour(Z,n) produces a contour plot of matrix Z with n contour levels.

contour(Z,v) draws a contour plot of Z with contour levels at the values specified in vector v.

contour(x,y,Z), contour(x,y,Z,n), and contour(x,y,Z,v) produce contour plots of Z and use the data in vectors x and y to control the axis scaling on the x- and y-axes. The elements of x and y are equally spaced.

C = contour(...) returns the contour matrix C as described in the function contourc and used by clabel.

To label the levels of a contour plot, see clabel.

Examples

To view a contour plot of the function

over the range -2 <= x <= 2, -2 <= y <= 3, use the statements:

x = -2:.2:2;
y = -2:.2:3;
[X,Y] = meshgrid(x,y);
Z = X.*exp(-X.^2-Y.^2);
contour(x,y,Z)

Diagnostics

If the smallest dimension of Z is less than 2:

Matrix must be 2-by-2 or larger.

Limitations

contour assumes that vectors x and y are monotonically increasing. If x and y are irregularly spaced, the contours are simply stretched apart, which is not the same as contouring the irregularly spaced data.

See Also

clabel, contour3, contourc, quiver

(c) Copyright 1994 by The MathWorks, Inc.