show regular intervals in the colourbar

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.

[Francesco Marchione]

I have developed this code:

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

[Vedant Shah]

Hi @Francesco Marchione,

To calculate a fixed number of evenly distributed values between the minimum and maximum, including the endpoints, the “linspace” function can be used. This function generates tick values that can be applied to the colorbar, ensuring visibility of both extremes and the specified number of intermediate intervals.

For detailed information about the “linspace” function, following documentation can be referred:

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

To implement the desired results, replace the existing line of code:

set(hcb, 'Ticks', sort([hcb.Limits, hcb.Ticks])) 

with:

numIntervals = 5; 
minValue = min(Zm(:)); 
maxValue = max(Zm(:)); 
tickValues = linspace(minValue, maxValue, numIntervals + 1); 
set(hcb, 'Ticks', tickValues); 

This modification ensures the output displays the required intervals effectively.