Colorbar, display regular intervals

I would like to have the colourbar displaying values for regular intervals: that is, I would like to have the colourbars displaying both extremes (max and min) and a fixed number of intermediate values (intervals), automatically.

I attach the xslx file

T1 = readtable('SLJ20 PEEL.xlsx', 'VariableNamingRule','preserve');

% First10Rows = T1(1:10,:)
% T1Sz = size(T1)
VarNames = T1.Properties.VariableNames;

N = 50;                                                                     % Interpolation Matrix Size
xv = linspace(min(T1{:,1}), max(T1{:,1}), N);                               % Create Vector
yv = linspace(min(T1{:,2}), max(T1{:,2}), N);                               % Create Vector
[Xm,Ym] = ndgrid(xv,yv);                                                    % Create Interpolation Matrices
Zm = griddata(T1{:,1}, T1{:,2}, T1{:,3}, Xm, Ym);                           % Interpolate

figure
surfc(Xm, Ym, Zm)
grid on

shading interp

set(0, 'DefaultTextInterpreter', 'latex')

hcb = colorbar;
xlabel(hcb,'[{\it Pa}]');
hcb.Label.Interpreter = 'latex';

set(hcb,'TickLabelInterpreter','latex')
colormap(jet(50))
title ('EPX1','FontSize',13,'interpreter', 'latex')
set(0, 'DefaultTextInterpreter', 'latex')


hcb = colorbar;
hcb.TickLabelInterpreter='latex';
% ColorbarRulerProperties = hcb.Ruler

hcb.Ruler.TickLabelFormat = '%.2f';

set(hcb, 'Ticks', sort([hcb.Limits, hcb.Ticks]))
set(gca,'TickLabelInterpreter','latex')
% tix = hcb.Ticks;
% expstr = @(x) [x(:).*10.^ceil(-log10(abs(x(:)+(x==0)))) floor(log10(abs(x(:)+(x==0))))];
% tixexp = expstr(tix(:))
% tixexplbl = compose('%.2f \\times 10^{%2d}',[tixexp(:,1) fix(tixexp(:,2))])
% hcb.TickLabels = tixexplbl;
xlabel('{\it x} [{\it mm}]')
ylabel('{\it y} [{\it mm}]')
zlabel('{\it} Shear stress [{\it MPa}]')

Answer 1

[Samay Sagar]

To have the colorbar display both extremes (max and min) and a fixed number of intermediate values at regular intervals automatically, you can set the “Ticks” property of the “colorbar” to a vector of values that spans from the minimum to the maximum of the data range, divided into equal intervals. You can do this using the “linspace” function.

Read more about “linspace” here:

https://www.mathworks.com/help/releases/R2021b/matlab/ref/linspace.html

Here's how you can modify your existing code to achieve this:

T1 = readtable('SLJ20 PEEL.xlsx', 'VariableNamingRule','preserve');
VarNames = T1.Properties.VariableNames;
N = 50;
xv = linspace(min(T1{:,1}), max(T1{:,1}), N);
yv = linspace(min(T1{:,2}), max(T1{:,2}), N);
[Xm,Ym] = ndgrid(xv,yv);
Zm = griddata(T1{:,1}, T1{:,2}, T1{:,3}, Xm, Ym);
figure
surfc(Xm, Ym, Zm)
grid on
shading interp
set(0, 'DefaultTextInterpreter', 'latex')
% Colorbar settings
hcb = colorbar;
xlabel(hcb,'[{\it Pa}]');
hcb.Label.Interpreter = 'latex';
set(hcb,'TickLabelInterpreter','latex')
colormap(jet(50))
title ('EPX1','FontSize',13,'interpreter', 'latex')
set(0, 'DefaultTextInterpreter', 'latex')
hcb = colorbar;
hcb.TickLabelInterpreter='latex';

% Define the number of intervals for the colorbar
numIntervals = 5;
cmin = min(Zm(:));
cmax = max(Zm(:));
ticks = linspace(cmin, cmax, numIntervals+1);
hcb.Ticks = ticks;
hcb.TickLabels = arrayfun(@(v) sprintf('%.2f', v), ticks, 'UniformOutput', false);

set(gca,'TickLabelInterpreter','latex')

xlabel('{\it x} [{\it mm}]')
ylabel('{\it y} [{\it mm}]')
zlabel('{\it} Shear stress [{\it MPa}]')

Read more about “Ticks” and “colobar” here:

https://www.mathworks.com/help/releases/R2021b/matlab/ref/colorbar.html#:~:text=project.org/.-,Ticks,-%E2%80%94%20Tick%20mark