CODEWITHSUNDEEP
matlab
shiftyscales
shiftyscales

Reputation: 465

'Cumulative' bar chart in MATLAB

I am trying to plot 5 histograms in one plot. To make this readable, I have thought of using a 'cumulative' (not sure whether this is the right term) bar chart, but couldn't find an easy implementation in MATLAB. Is there one ?

Here is an example of what I am talking about:

a=1:5
b=5:-1:1

when I try a normal bar chart, it would look like this:

bar([a ;b]')

enter image description here

and what I want is this (excuse hasty image editing): enter image description here

I cannot achieve this with using 'bar' twice with 'hold on', since one of the bar charts will cover the other one.

ps: if there are better ways of plotting multiple histograms on the plot, except using density curves, please feel free to advise :)

Upvotes: 3

Views: 1472

Answers (1)

tyogi
tyogi

Reputation: 650

I believe you might be looking for :

bar([a ;b]', 'stacked')

=== EDIT 1 ===

Looking more closely at your drawing, you might also be looking for a less conventional "stacking" which you can achieve by superimposing both bars like so :

a=(1:5)';
b=(5:-1:1)';
c = a;
c(b<=a)=nan;
figure;
subplot(1,2,1);
bar([a,b]);
subplot(1,2,2);
hold on;
bar(a,'b');
bar(b,'r');
bar(c,'b');
hold off

This yields the following figure, which is similar to yours: enter image description here

=== END OF EDIT 1 ===

=== EDIT 2 ===

here is an implementation of what i was suggesting in my comments to extend that idea to an arbitrary number of series. basically, each layer (from tallest to smallest) is painted (using patch) in a loop. Although this is not a Matlab Bar chart anymore (which, to my knowledge, cannot solve your problem due to the fact that independent horizontal bars for a given serie cannot be accessed through uistack), the resulting figure fits the description you gave.

function testBarOverlay()
    % data initialization
    nbSeries = 8;
    nbBars = 5;
    xt = 1:nbBars;
    data = rand( nbBars, nbSeries );

    %draw (then erase) figure and get the characteristics of Matlab bars (axis, colors...)
    figure;
    h = bar( data( :, 1 ) );
    width = get( h, 'barWidth' );
    delete( h );

    % sort in order to start painting the tallest bars
    [ sdata, idx ] = sort( data, 2 );

    % get the vertices of the different "bars", drawn as polygons
    x = [ kron( xt, [1;1] ) - width / 2; kron( xt, [1;1] ) + width / 2 ];

    % paint each layer, starting with the 'tallest' ones first
    for i = nbSeries : -1 : 1
        y = [ zeros( nbBars, 1 ), sdata( :, i ), sdata( :, i ), zeros( nbBars, 1 ) ]';
        p = patch( x, y, 'b' );
        set( p, 'FaceColor', 'Flat', 'CData', idx( :, i )' );
    end
end

enter image description here

=== END OF EDIT 2 ===

Upvotes: 4

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