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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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(gcf);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
Dashed Contour Lines
Create a contour plot, and specify the dashed line style.
[X,Y,Z] = peaks;
contourf(X,Y,Z,'--')
fig2plotly(gcf);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
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(gcf);
Unrecognized field name "Fill". We had trouble parsing the contour object. This trace might not render properly.
Contour Plot with Histogram Subplots
t = linspace(-1, 1.2, 2000);
x = (t.^3)+(0.3.*randn(1, 2000));
y = (t.^6)+(0.3.*randn(1, 2000));
trace1 = struct(...
'x', x, ...
'y', y, ...
'mode', 'markers', ...
'name', 'points', ...
'marker', struct(...
'color', 'rgb(102,0,0)', ...
'size', 2, ...
'opacity', 0.4), ...
'type', 'scatter');
trace2 = struct(...
'x', x, ...
'y', y, ...
'name', 'density', ...
'ncontours', 20, ...
'colorscale', 'Hot', ...
'reversescale', true, ...
'showscale', false, ...
'type', 'histogram2dcontour');
trace3 = struct(...
'x', x, ...
'name', 'x density', ...
'marker', struct('color', 'rgb(102,0,0)'), ...
'yaxis', 'y2', ...
'type', 'histogram');
trace4 = struct(...
'y', y, ...
'name', 'y density', ...
'marker', struct('color', 'rgb(102,0,0)'), ...
'xaxis', 'x2', ...
'type', 'histogram');
data = {trace1, trace2, trace3, trace4};
layout = struct(...
'showlegend', false, ...
'autosize', false, ...
'width', 600, ...
'height', 550, ...
'xaxis', struct(...
'domain', [0, 0.85], ...
'showgrid', false, ...
'zeroline', false), ...
'yaxis', struct(...
'domain', [0, 0.85], ...
'showgrid', false, ...
'zeroline', false), ...
'margin', struct('t', 50), ...
'hovermode', 'closest', ...
'bargap', 0, ...
'xaxis2', struct(...
'domain', [0.85, 1], ...
'showgrid', false, ...
'zeroline', false), ...
'yaxis2', struct(...
'domain', [0.85, 1], ...
'showgrid', false, ...
'zeroline', false));
plotly(data, struct('layout', layout));