MATLAB Function Reference

contour3 - 3-D contour plot

GUI Alternatives

To graph selected variables, use the Plot Selector in the Workspace Browser, or use the Figure Palette Plot Catalog. Manipulate graphs in plot edit mode with the Property Editor. For details, see "Plotting Tools — Interactive Plotting" in the MATLAB^® Graphics documentation and "Creating Graphics from the Workspace Browser" in the MATLAB Desktop Tools and Development Environment documentation.

Syntax

contour3(Z) contour3(Z,n) contour3(Z,v) contour3(X,Y,Z) contour3(X,Y,Z,n) contour3(X,Y,Z,v) contour3(...,LineSpec) contour3(axes_handle,...) [C,h] = contour3(...)

Description

contour3 creates a 3-D contour plot of a surface defined on a rectangular grid.

contour3(Z) draws a contour plot of matrix Z in a 3-D view. Z is interpreted as heights with respect to the x-y plane. Z must be at least a 2-by-2 matrix that contains at least two different values. The number of contour levels and the values of contour levels are chosen automatically. The ranges of the x- and y-axis are [1:n] and [1:m], where [m,n] = size(Z).

contour3(Z,n) draws a contour plot of matrix Z with n contour levels in a 3-D view.

contour3(Z,v) draws a contour plot of matrix Z with contour lines at the values specified in vector v. The number of contour levels is equal to length(v). To draw a single contour of level i, use contour(Z,[i i]).

contour3(X,Y,Z), contour3(X,Y,Z,n), and contour3(X,Y,Z,v) use X and Y to define the x- and y-axis limits. If X is a matrix, X(1,:) defines the x-axis. If Y is a matrix, Y(:,1) defines the y-axis. When X and Y are matrices, they must be the same size as Z, in which case they specify a surface as surf does.

contour3(...,LineSpec) draws the contours using the line type and color specified by LineSpec.

contour3(axes_handle,...) plots into the axes with the handle axes_handle instead of into the current axes (gca).

[C,h] = contour3(...) returns the contour matrix C, as described in the function contourc and a column vector h, containing handles to graphics objects. contour3 creates patch graphics objects unless you specify LineSpec, in which case contour3 creates line graphics objects.

Remarks

If X or Y is irregularly spaced, contour3 calculates contours using a regularly spaced contour grid, and then transforms the data to X or Y.

If you do not specify LineSpec, colormap and caxis control the color.

contour3(...) works the same as contour(...) with these exceptions:

The contours are drawn at their corresponding Z level.
Multiple patch objects are created instead of a contourgroup.
Calling contour3 with trailing property-value pairs is not allowed.

Examples

Plot the three-dimensional contour of a function and superimpose a surface plot to enhance visualization of the function.

[X,Y] = meshgrid([-2:.25:2]);
Z = X.*exp(-X.^2-Y.^2);
contour3(X,Y,Z,30)
surface(X,Y,Z,'EdgeColor',[.8 .8 .8],'FaceColor','none')
grid off
view(-15,25)
colormap cool