# Plot histogram for multiple cases in 3 dimensions

117 views (last 30 days)
A Lotgering on 11 Dec 2015
Edited: Torsten on 13 Aug 2022
Hi, I'm Alex and I would like to ask a question regarding the possibilities of a histogram plot.
I like to plot a "2D" histogram from a 30 by N matrix. In this 30 by N matrix data from a Monte Carlo simulation is stored for 30 different cases. The data stored in de N colums can be used for the "2D" histogram plot. However, there comes the problem. I like to plot a "2D" histogram of every case into one single '3D' plot.
If you take axis x,y,z. The plot would be something like: Horizontal x-axis is for the data stored in the N columns (Data from Monte Carlo simulation). The Vertical y-axis is for the frequency of those values to create a histogram (I call this 2D). The Horizontal z-axis is for the 30 different cases for which I like to create a similar histogram in the x- and y-axis.
The confusion is the way "2D" or "3D" histograms work. I'm not interested in a comparison histogram between the values of every case. I simply want to show every histogram into one single figure so I can show the trent between the different cases.
Is this even possible with histograms or should we use a different plot style?

Satyajeet Sasmal on 15 Dec 2015
Hi Andy,
Have you tried using the "hist3" and bar3 functions? Please see the sample code below:
vec_x = [1 2 4 5 7 8 9 3 8 7 2]';
vec_y = [1 3 9 5 7 8 1 3 2 9 2]';
vec_bin_edges = 0:9;
hist3([vec_x vec_y], 'Edges', {vec_bin_edges, vec_bin_edges});
mat_joint = hist3([vec_x vec_y], 'Edges', {vec_bin_edges, vec_bin_edges});
figure
bar3(mat_joint, 1);
axis tight
Here are the documentation links for bar3 and hist3 respectively:
-Satya

A Lotgering on 16 Dec 2015
Edited: Torsten on 13 Aug 2022
I found the answer:
The following worked for me. It seems like you just want a histogram for each of the 30 cases. If so, this is done very simply using histc and bar3 (essentially just two lines of code; three if you don't use the default edges):
rng(0);
% make dummy data
ncases = 30;
N = 1000;
data = NaN(ncases, N);
for k = 1:ncases
% generate a dummy random-normal distribution
% with random mean and random standard deviation
data(k, :) = rand(1) + rand(1)*randn(N, 1);
end
% generate data for histograms: 1 histogram per column
edges = [-5:0.5:5]; % bin edges
counts = histc(data, edges, 2); % specify dim 2 to act column-wise
% plot results
hf = figure;
ha = axes;
hb = bar3(edges, counts.'); % note the transpose to get the colors right
xlabel('case number')
ylabel('bins');
zlabel('count');
##### 2 CommentsShowHide 1 older comment
Belal Essam on 20 Nov 2021
Thank you @A Lotgering.

### Categories

Find more on Histograms in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!