How can I create a surface plot (with height in Z) from X-Y coordinates and Z as a matrix?

I try to plot a surface plot (with height in Z) from X-Y coordinates and Z as a matrix.

X and Y are my coordinates from 1 to 100 and Z is a matrix containing the values I want to plot as a surface.

Here, my Z matrix is called mymatrix.

I tried to use the commands pcolor and surf but instead of getting a surface with surf I still get the same plot as the one generated with pcolor.

I have attached the figures I get as well as mymatrix.

Here is what I tried:

%% pcolor command
figure(1)
clf;
hold on;
pcolor(mymatrix);
cb = colorbar;
xlim([1 100]);
ylim([1 100]);
title(['pcolor command'],'FontSize', 24, 'FontWeight', 'Bold');

%% surf command
[X,Y] = meshgrid(1:100,1:100);

figure(2)
clf;
hold on;
grid on;
grid minor;
xlim([1 100]);
ylim([1 100]);
surf(X,Y,mymatrix);
cb = colorbar;
title(['surf command'],'FontSize', 24, 'FontWeight', 'Bold');

Does anyone know how to produce a surface plot with height and colours as the third dimension of my plot?

Thank you

Answer 1

[Cris LaPierre]

Remove the clf and hold on commands from your plotting commands.

The coloring is already done by height, but by default, each panel is a solid color, with the color being determined by the Z value on the left/bottom edge. Change your FaceColor property to 'interp' to apply a gradient.

load mymatrix.mat

figure(2)
grid on
grid minor
surf(1:100,1:100,mymatrix,'LineStyle',"none","FaceColor","interp")
cb = colorbar;
title(['surf command'],'FontSize', 24, 'FontWeight', 'Bold')

[A LL]

Thank you very much Cris LaPierre for your answer!

Do you happen to know how to make the black meshgrid lines appear on the surface plot to help with the visualization?

[Cris LaPierre]

Not easily. Grid lines are drawn on the box containing the axes. You'd have to manually add the lines to your surface using secondary plot commands.

[A LL]

ok, thanks again!

Answer 2

[KSSV]

load('mymatrix.mat') ; 
surf(mymatrix) ;
shading interp 
colorbar

[A LL]

Thank you very much KSSV for your answer!

Do you happen to know how to make the black meshgrid lines appear on the surface plot to help with the visualization?

[KSSV]

load('mymatrix.mat') ; 
surf(mymatrix) ;
colorbar

Don't use shading interp.

[A LL]

great! Thanks KSSV!