MATLAB: How to plot a histogram as a curve

histogramMATLABplot

I have a histogram that I want to plot just as a simple line plot. I have tried:

h = histogram(speed,'Normalization','probability')
plot(h)

But then I got an error message: Not enough input arguments.

Does anyone know how I can do it? Many thanks!

Best Answer

[N,edges] = histcounts(X, 'Normalization','pdf');
edges = edges(2:end) - (edges(2)-edges(1))/2;
plot(edges, N);

Personally I just do a simple calculation from histcounts

Related Solutions

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!

MATLAB: How to get the data as output along with the histogram plot

You could request output from histogram():

h = histogram(S,'Normalization','probability');

and access properties such as h.BinEdges, h.BinCounts, h.Values, etc, described here.

Or you could use histcounts(), described here, after you plot your histogram:

histogram(S,'Normalization','probability');
[binCounts,binEdges] = histcounts(S,'Normalization','probability');

Best Answer

Related Solutions

MATLAB: Normalized distribution for histogram

MATLAB: How to get the data as output along with the histogram plot

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