MATLAB: Change colors for each bins in histogram

histogram bins color

Hi, I have attached sample data, I plot histogram for the sample data as: hist = histogram(sample)

I need to color each bin(group of values) in different, and put annotation text in figure what each color represent :

Best Answer

From R2014b onwards, the only way to do it is to bar() in each entry one at a time, specifying the color you want. Well, you could also use patch() or fill() or rectangle() to put in the bars; the point is that histogram objects do not allow you to change the bar colors individually now.

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MATLAB: How to get only selected legend in this particular case

Using explicit handles to the patch objects will fix the legend for you. Also, you don't need the second call to hold on. The last part of the code will delete all line objects in the plot. If you want to change the legend labels, look into the doc for the legend function.

S=load('matlab.mat');D=S.D;I=S.I;NO=S.NO;
figure(1),clf(1)
yt = logspace(-3,4,8);
binranges = yt; 
[bincounts] = histc((I(:,1)),binranges); 
h1 = bar(binranges,bincounts,'histc');
set(h1,'FaceColor','r','EdgeColor','r');
hold on;
[bincounts] = histc(1./(D(:,1)),binranges); 
h2 = bar(binranges,bincounts,'histc');
set(h2,'FaceColor','g','EdgeColor','g');
%hold on;%redundant, as the NextPlot property is already set
[bincounts] = histc((NO(:,1)),binranges); 
h3 = bar(binranges,bincounts,'histc');
set(h3,'FaceColor','b','EdgeColor','b');
legend([h1 h2 h3]);%use handles to patch objects
set(gca,'XMinorTick','on','YMinorTick','on','XScale','log');
children=get(gca,'Children');
types=get(children,'Type');
delete(children(ismember(types,{'line'})))

MATLAB: Normalized distribution for histogram

If you have the Statistics Toolbox, you might find the dfittool distribution fitting tool quite useful.

doc dfittool

If not, you can normalize a histogram by scaling the counts in each bin. With the normalized counts, you can plot both the normalized histogram and your curve. The trick is to identify the appropriate scaling factor.

Here is some example code where I plot the normal probability with the normalized histogram data:

% Arbitrary data generation and statistics
dataVec = randn(1000,1);
muData = mean(dataVec);
stdData = std(dataVec);
% Defining the bin centers
binStep    = 0.1;
binCenters = -5:binStep:5;
% Compute the histogram scaling factor. (If all histogram counts are in a
% single bin, the probability = 1)
binCount   = histc(dataVec,binCenters);
probScale  = sum(binCount)*binStep;
% Plot the normalized histogram and change the bar color for line
% visibility
histHandle = bar(binCenters,binCount/probScale,'hist');
set(histHandle,'FaceColor',[1,1,1]); 
hold on;
% Overlay the distribution fit on the histogram
x = binCenters;
y = normpdf(x,muData,stdData);
plot(x,y);
xlabel('Data');
ylabel('Probability');

Hope this helps to get you started!

Best Answer

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MATLAB: Normalized distribution for histogram

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