MATLAB contourf in MATLAB^®

Learn how to make 7 contourf charts in MATLAB, then publish them to the Web with Plotly.

Contours of Peaks Function

Define Z as a function of two variables. In this case, call the peaks function to create Z. Then display a filled contour plot of Z, letting MATLAB® choose the contour levels.

Z = peaks;
contourf(Z)

fig2plotly()

Contours at Ten Levels

Define Z as a function of two variables, X and Y. Then display contours at 10 levels of Z.

x = linspace(-2*pi,2*pi);
y = linspace(0,4*pi);
[X,Y] = meshgrid(x,y);
Z = sin(X) + cos(Y);
contourf(X,Y,Z,10)

fig2plotly()

Contours at Specific Levels with Labels

Define Z as a function of X and Y. In this case, call the peaks function to create X, Y, and Z. Then display contours at levels 2 and 3.

The white region corresponds to the heights less than 2. The purple region corresponds to heights between 2 and 3. And the yellow region corresponds to heights that are greater than 3.

[X,Y,Z] = peaks(50);
contourf(X,Y,Z,[2 3],'ShowText','on')

fig2plotly()

Contours at One Level

Define Z as a function of X and Y. In this case, call the peaks function to create X, Y, and Z. Then display contours at Z = 2.

[X,Y,Z] = peaks;
contourf(X,Y,Z,[2 2])

fig2plotly()

Dashed Contour Lines

Create a contour plot, and specify the dashed line style.

[X,Y,Z] = peaks;
contourf(X,Y,Z,'--')

fig2plotly()

Custom Line Width

Create a filled contour plot. Make the contour lines thicker by setting the LineWidth property to 3.

Z = peaks;
[M,c] = contourf(Z);
c.LineWidth = 3;

fig2plotly()

Contours Over Discontinuous Surface

Insert NaN values wherever there are discontinuities on a surface. The contourf function does not draw contour lines in those regions.

Define matrix Z as a sampling of the peaks function. Replace all values in column 26 with NaN values. Then plot the contours of the modified Z matrix.

Z = peaks;
Z(:,26) = NaN;
contourf(Z)

fig2plotly()