Contour Plots in MATLAB®
How to make Contour Plots plots in MATLAB® with Plotly.
Contours of a Function
Create matrices X
and Y
, that define a grid in the x-y plane. Define matrix Z
as the heights above that grid. Then plot the contours of Z
.
x = linspace(-2*pi,2*pi);
y = linspace(0,4*pi);
[X,Y] = meshgrid(x,y);
Z = sin(X)+cos(Y);
contour(X,Y,Z)
fig2plotly(gcf);
Contours at Twenty Levels
Define Z
as a function of X
and Y
. In this case, call the peaks
function to create X
, Y
, and Z
. Then plot 20 contours of Z
.
[X,Y,Z] = peaks;
contour(X,Y,Z,20)
fig2plotly(gcf);
Contours at One Level
Display the contours of the peaks
function at Z = 1
.
[X,Y,Z] = peaks;
v = [1,1];
contour(X,Y,Z,v)
fig2plotly(gcf);
Dashed Contour Lines
Create a contour plot of the peaks
function, and specify the dashed line style.
[X,Y,Z] = peaks;
contour(X,Y,Z,'--')
fig2plotly(gcf);
Contours with Labels
Define Z
as a function of two variables, X
and Y
. Then create a contour plot of that function, and display the labels by setting the ShowText
property to 'on'
.
x = -2:0.2:2;
y = -2:0.2:3;
[X,Y] = meshgrid(x,y);
Z = X.*exp(-X.^2-Y.^2);
contour(X,Y,Z,'ShowText','on')
fig2plotly(gcf);
Custom Line Width
Create a contour plot of the peaks
function. Make the contour lines thicker by setting the LineWidth
property to 3
.
Z = peaks;
[M,c] = contour(Z);
c.LineWidth = 3;
fig2plotly(gcf);
Contours Over Discontinuous Surface
Insert NaN
values wherever there are discontinuities on a surface. The contour
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;
contour(Z)
fig2plotly(gcf);
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 MATLABĀ® choose the contour levels.
Z = peaks;
contourf(Z)
fig2plotly(gcf);
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(gcf);
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(gcf);
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(gcf);
Dashed Contour Lines
Create a contour plot, and specify the dashed line style.
[X,Y,Z] = peaks;
contourf(X,Y,Z,'--')
fig2plotly(gcf);
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(gcf);