Multiple colormap in one figure

Hi,

I am trying to plot two 3D surface plot with different colormap in one figure.

Do not really know why the freezeColors is not working for me.

Here is my code I took the freezecolor off:

clear all

clc

close all

% Data reading from Excel - 1

x1 = xlsread('temp.xlsx', 'Sheet1', 'B:B');

y1 = xlsread('temp.xlsx', 'Sheet1', 'D:D');

z1 = xlsread('temp.xlsx', 'Sheet1', 'E:E');

xv1 = linspace(min(x1), max(x1), 50);

yv1 = linspace(min(y1), max(y1), 145);

[XX_1,YY_1] = meshgrid(xv1, yv1);

ZZ_1 = griddata(x1,y1,z1,XX_1,YY_1);

% Plotting

figure

plot1=mesh(XX_1,YY_1,ZZ_1);

colormap(jet)

shading interp

set(plot1,'FaceAlpha',0.5);

axis equal

%-----------------------------------------------------------------------------------------------

% Data reading from Excel - 2

x2 = xlsread('temp.xlsx', 'Sheet1', 'I:I');

y2 = xlsread('temp.xlsx', 'Sheet1', 'J:J');

z2 = xlsread('temp.xlsx', 'Sheet1', 'K:K');

xv2 = linspace(min(x2), max(x2), 50);

yv2 = linspace(min(y2), max(y2), 145);

[XX_2,YY_2] = meshgrid(xv2, yv2);

ZZ_2 = griddata(x2,y2,z2,XX_2,YY_2);

% Plotting

hold on

plot2=surf(XX_2,YY_2,ZZ_2);

colormap(hot)

shading interp

set(plot2,'FaceAlpha',0.8);

%-----------------------------------------------------------------------------------------------

% Polish graph

hold off

title('Interface Temp')

xlabel('Y (mm)')

ylabel('X (mm)')

zlabel('Temperature (^{\circ}C)')

colorbar

view(45,45)

grid off

Thanks.

Answer 1

[Vedant Shah]

Hi @Teoh Jun Chang,

A single axes object in MATLAB can only have one colormap at a time. When ‘colormap(jet)’ is called followed by ‘colormap(hot)’, the second call overwrites the first, resulting in both surfaces using the last colormap applied.

One possible solution is to overlay two axes in the same figure, assigning a different colormap to each, and setting their backgrounds to be transparent. This approach allows each surface to retain its respective colormap. The following code snippet demonstrates this method:

% Plotting 
figure 
set(gcf, 'Color', 'w') 

% First axes 
ax1 = axes; 
mesh1 = mesh(XX_1, YY_1, ZZ_1); 
colormap(ax1, jet) 
shading interp 
set(mesh1, 'FaceAlpha', 0.5) 
axis equal 
hold(ax1, 'on') 

% Second axes, placed in the same position 
ax2 = axes; 
mesh2 = surf(XX_2, YY_2, ZZ_2); 
colormap(ax2, hot) 
shading interp 
set(mesh2, 'FaceAlpha', 0.8) 

% Overlay axes: make both transparent 
set(ax1, 'Color', 'none') 
set(ax2, 'Color', 'none', ... 
    'XTick', [], 'YTick', [], 'ZTick', [], ... 
    'XColor', 'none', 'YColor', 'none', 'ZColor', 'none') 

linkaxes([ax1, ax2]) 

Using this approach with sample data, each surface can be visualized with its own colormap, resulting in a figure as shown below:

For further information, refer to the following documentations:

• https://www.mathworks.com/help/matlab/ref/set.html
• https://www.mathworks.com/help/matlab/ref/axis.html
• https://www.mathworks.com/help/matlab/ref/linkaxes.html
• https://www.mathworks.com/help/matlab/ref/surf.html
• https://www.mathworks.com/help/matlab/ref/mesh.html