Matlab 3D surface normal distribution

Question

I have two normal distributions and i am trying to make a volumetric surface from them. I got the following graph

enter image description here

clear; clc;

nsamp = 100000;

%

% Basic variables

%

m1=2.724;

dp1=0.375;

R = normrnd(m1,dp1, nsamp, 1);

m2=1.345;

dp2=0.135;

S = normrnd(m2,dp2, nsamp, 1);

%

Z = R - S;


    I = (Z < 0);

pf = sum(I)/nsamp

beta = -norminv(pf)

%

% Histograms

hist(S,20)

hold on

hist(R,40)

set(findobj('Type','patch'),'Facecolor','none','Edgecolor','black')

set(gca,'Fontsize',18,'Fontname','euclid')

xlabel('R & S')


figure

scatterhist(R,S)

xlabel('R'),ylabel('S')

and i would like to make a 3D surface and the points in red to remain in red and the blue points in blue. Can someone help me? Regards

"volume" implies three dimensions. What would you like the third dimension to represent? — Floris
<jitkomut.lecturer.eng.chula.ac.th/matlab/_images/gaussian8.png The frequency of the result function density. — blitzstat
That is the pretended surface. But the colors are not. I would like to be blue and red only. Thanks mate! — blitzstat
Sorry to keep bugging for details - but how do you want the colors to show up. Do you want two surfaces - one all blue, and one all red? Or do you want a single Gaussian that is more blue when it's blue, and more red when it's red? It's hard to read your mind on this... — Floris
If you run that code you can see two types of points: red and blue. I would like a single Gaussian surface that is blue and red at the same time, according to the I vector. I dont know if i explained myself in the proper way... Sorry mate and thanks a lot for your dedication and time! :) — blitzstat

Floris Floris · Accepted Answer · 2014-11-03T04:14:55

I can't write a tested solution right now - not access to Matlab license server. But you have two problems here.

The first is to create a surface plot of density. You can use the hist3 function for the this - and if you return the values of the bins you can control the plotting yourself:

[N C] = histc(X)

(I'm sorry it is not clear to me what you really want to plot - is it R, S, Z, or R+S? that's why I used X).

Then to color the graph, you can use patch coloring - see http://www.mathworks.com/help/matlab/visualize/specifying-patch-coloring.html for how to do that.

The combination of these two should get you a long way there... but it's still a little unclear what you really want to do. I hope these hints help you on your way.

Matlab 3D surface normal distribution

1 Answers