How do I color the bars of my stacked bar chart based on another variable?

I have created a horizontal bar chart with one stack. I have an array "duration" that describes how wide each bar should be. When I plot the stacked bar chart as below, the colors are assigned automatically:

>> duration = [1 2 3 4 5 4 3 2 1];
>> b = barh(0,duration,'stacked');

However, I want to assign the colors based on another variable, "satisfaction", which is an array of doubles.

>> satisfaction = [12 22 34 42 51 63 77 84 95];

How can I assign colors to my bars based on this array of doubles?

Answer 1

[MathWorks Support Team]

A possible solution is to map your "satisfaction" data onto a colormap, then assign a color to each bar in your chart based on that colormap:

https://www.mathworks.com/help/matlab/ref/bar.html#d117e81991

To do so, first set the "FaceColor" of the bars to "flat":

>> ax = axes;
>> b = barh(ax,0,duration,'stacked','FaceColor','flat');

Then, change the axes color limits to match those of your "satisfaction" data:

>> ax.CLim = [min(satisfaction) max(satisfaction)];

To label the colorbar and the x-axis of the plot, we write:

>> c = colorbar;
>> c.Label.String = 'Satisfaction';
>> xlabel('Duration');

Once the colormap is setup, you can assign each bar's "CData" to the corresponding "satisfaction" value:

for i = 1:length(duration)
  b(i).CData = satisfaction(i);
end

This will produce the color mapping you expect. You can also change the scale of the colormap from linear to logarithmic by using the "ColorScale" property on the axes:

https://www.mathworks.com/help/matlab/ref/matlab.graphics.axis.axes-properties.html#budumk7-ColorScale

For example,

>> ax.ColorScale = "log";

I have attached a file to this post, combining all the steps described above into a single script.