How to change heatmap data labels

I am trying to use heatmap() to generate a heatmap like this:

But I need to be able to change the values that are used in each cell. Instead of using the raw data value I would like to change each cell to have a label. I don't see any ovbious way to do this using the figure properties so I am wondering if this is possible.

Answer 1

[Adam Danz]

Modifications to heatmap are not easy. I suggest recreating the heatmap using imagesc which will look almost exactly the same but will not have some of the interactivity options.

Example:

Generate data

rng('default') % for reproducibility
data = magic(5);

Create heatmap

figure()
heatmap(data)
title('heatmap')

Create imagesc plot that looks like a heatmap

This uses the same input data, data.

fig = figure();
ax = axes(fig);
h = imagesc(ax, data);
set(ax,'XTick',1:5,'YTick',1:5)
title('imagesc')
ax.TickLength(1) = 0;

% Create heatmap's colormap
n=256;
cmap = [linspace(.9,0,n)', linspace(.9447,.447,n)', linspace(.9741,.741,n)'];

colormap(ax, cmap); 
colorbar(ax)
hold on

% Set grid lines
arrayfun(@(x)xline(ax,x,'k-','Alpha',1),0.5:1:5.5)
arrayfun(@(y)yline(ax,y,'k-','Alpha',1),0.5:1:5.5)
% Starting in R2021, xline and yline accept object arrays
% and you can replace the two lines above with these two lines
%   xline(ax,ax.XTick+0.5,'k-','Alpha',1)
%   yline(ax,ax.YTick+0.5,'k-','Alpha',1)

Specify text labels

Lables here are random characters

asc = [65:90, 97:122]; 
nLabels = 25;
labels = mat2cell(char(asc(randi(numel(asc), nLabels, 4))),ones(nLabels,1),4);

[xTxt, yTxt] = ndgrid(1:5, 1:5); 
th = text(xTxt(:), yTxt(:), labels(:), ...
    'VerticalAlignment', 'middle','HorizontalAlignment','Center');

[Hal Owens]

Appreciate the help this should work for my use case.