contour3

Three-dimensional contour plot

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)
[C,h] = contour3(...)

Description

contour3 creates a three-dimensional contour plot of a surface defined on a rectangular grid.

contour3(Z) draws a contour plot of matrix Z in a three-dimensional view. Z is interpreted as heights with respect to the x-y plane. Z must be at least a 2-by-2 matrix. 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 three-dimensional 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.

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

Remarks

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

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

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





contourf

Filled two-dimensional contour plot

Syntax

*

contourf(Z)
contourf(Z,n)
contourf(Z,v)
contourf(X,Y,Z)
contourf(X,Y,Z,n)
contourf(X,Y,Z,v)
[C,h,CF] = contourf(...)

Description

A filled contour plot displays isolines calculated from matrix Z and fills the areas between the isolines using constant colors. The color of the filled areas depends on the current figure's colormap.

contourf(Z) draws a contour plot of matrix Z, where Z is interpreted as heights with respect to a plane. Z must be at least a 2-by-2 matrix. The number of contour lines and the values of the contour lines are chosen automatically.

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

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

contourf(X,Y,Z), contourf(X,Y,Z,n), and contourf(X,Y,Z,v) produce contour plots of Z using X and Y to determine the x- and y-axis limits. When X and Y are matrices, they must be the same size as Z, in which case they specify a surface as surf does.

[C,h,CF] = contourf(...) returns the contour matrix C as calculated by the function contourc and used by clabel, a vector of handles h to patch graphics objects, and a contour matrix CF for the filled areas.

Remarks

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

Examples

Create a filled contour plot of the peaks function.

*

[C,h] = contourf(peaks(20),10);
colormap autumn