MATLAB Answers

How to: Control Histogram bin width

Asked by Hello kity on 4 Feb 2013


Matlab chooses its own bin width when u use hist().

But I want, for example to make an histogram which makes bins of each 0.5 width. I noticed that hist uses the entire data range as range.

bin_width ( get from edit field)

bins= bin_width * range
[n xout]= hist (data, bins)

this still makes random hist where u dont have control over the bins.

what i want is,select the bin_width , 0.5 , plot first bin between 0 - 0.5 , second 0.5- 1 etc.




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2 Answers

Answer by per isakson
on 4 Feb 2013
 Accepted answer


    doc histc


Answer by Hello kity on 4 Feb 2013
Edited by Hello kity on 4 Feb 2013

I found an answer at google, adjusted some, hope it is useful.

With this code you can manually select the stepsize of the hist bins, for example, stepsize is 1. then it plots a bin from 0-1 ,1- 2 etc. IT also plots the amount of each bin on top of it.

xStep=str2double(get(handles.xstep1,'String'));    % edit field where is used a input for xstep        
                 xbounds = xlim;
          nBins = (xbounds(2)-xbounds(1))/xStep;
          edges = linspace(xbounds(1),xbounds(2), nBins+1);
          %# compute center of bins (used as x-coord for labels)
          bins = ( edges(1:end-1) + edges(2:end) ) / 2;
          %# histc
          [counts,binIdx] = histc(DATA, edges);
          counts(end-1) = sum(counts(end-1:end));  %# combine last two bins
          counts(end) = [];                        %#
   %         %# plot histogram
          bar(edges(1:end-1), counts, 'histc')
                      for c=1:numel(counts)
                          if counts(c)~=0
                              text(bins(c), counts(c)+0.3, num2str(counts(c)), 'FontWeight','bold', 'FontSize',8, ...
                                  'VerticalAlignment','bottom', 'HorizontalAlignment','center');
                      set(gca,'ylim',[0 max(counts)+1/10*(max(counts))]); %adjust ymax


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