Plot 2d and 3d Matrix

Hi! I have 2 matrix. One is a 2180x10 matrix (pressure) and the other is a 2180x10x3 matrix ( deformation in the x,y,z coordinates). I want to plot pressure (2d matrix) in funtion of de deformation (3d matrix). How could I do it?

Answer 1

[Walter Roberson]

It was a bit tricky to figure out a meaningful way to plot that. I had to assume that you are starting with an X Y grid with originally constant Z, and deformation is taking place at each point, and the deformation is moving the nodes a bit in the X, Y, and Z directions. In order to plot, I had to assume that the deformation array gives the relative movement on the node positions, and that you wanted to plot the pressure at the final position of each node.

%create test data. These are not expected to have anything to do with
%your real data, but I needed *some* data of the right size to experiment with

deformation = sort( rand(2810, 10, 3)/10 );

[px, py] = ndgrid(linspace(-3,3,2810), linspace(-3,3,10));
pressure  =  3*(1-px).^2.*exp(-(px.^2) - (py+1).^2) ...
 - 10*(px/5 - px.^3 - py.^5).*exp(-px.^2-py.^2) ...
 - 1/3*exp(-(px+1).^2 - py.^2);

%now do the drawing

dx = deformation(:,:,1);
dy = deformation(:,:,2);
dz = deformation(:,:,3);

nrow = size(dx,1);
ncol = size(dx,2);
[X, Y] = ndgrid(1:nrow, 1:ncol);
X = X + dx;
Y = Y + dy;
Z = dz;

surf(X, Y, Z, pressure, 'edgecolor', 'none')

If, instead, your deformation array is already the absolute positions that each node ends up at, then it could be as simple as:

X = deformation(:,:,1);
Y = deformation(:,:,2);
Z = deformation(:,:,3);
surf(X, Y, Z, pressure, 'edgecolor', 'none')

[Andrea Hern{andez]

it says me

 Warning: Error creating or updating Surface
 Error in value of property  CData
 Array is wrong shape or size "

The code is

%pressure datas

%read file

a=load('presion.txt');
p=a(:,2);
p(21802:21810)=2.03;
m=length(p)/10;%number of rows
n=10; %number of columns
i=1;
pressure=zeros(m,n);

%iteracion para formar matriz de 10 columna 

while i<=length(a)
    for k=1:n
        for j=1:m
        pressure(j,k)=p(i); 
        i=i+1;
        end
    end
end

%position data

%read file

b=load('deformacion.txt');
x=b(:,1); %x coordinate
y=b(:,2); %y coordinate
z=b(:,3); %z coordinate
x(21796:21800)=-5.29325;
y(21796:21800)=-7.553305;
z(21796:21800)=721.812683;

m=length(x)/10; %numer of rows
n=10; %number of columns

%Matrix of 10 columns

%x position 

i=1;
X=zeros(m,n);

while i<=length(x)
    for k=1:n
        for j=1:m
        X(j,k)= x(i);
        i=i+1;
        end
    end
end

%y position

i=1;
Y=zeros(m,n);

while i<=length(x)
    for k=1:n
        for j=1:m
        Y(j,k)= y(i);
        i=i+1;
        end
    end
end

%z position

i=1;
Z=zeros(m,n);

while i<=length(x)
    for k=1:n
        for j=1:m
        Z(j,k)= z(i);
        i=i+1;
        end
    end
end

%initial position

xo=-7.90365;
yo=-5.435417;
zo=721.961304;

%deformation coordinates

dx=xo-X;
dy=yo-Y;
dz=zo-Z;

%deformation matrix 

deformation = cat(3,dx,dy,dz);

%plot

DX=deformation(:,:,1);
DY=deformation(:,:,2);
DZ=deformation(:,:,3);

nrow = size(DX,1);
ncol = size(DX,2);
[coordinatex, coordinatey] = ndgrid(1:nrow, 1:ncol);
coordinatex = coordinatex+ DX;
coordinatey = coordinatey + DY;
coordinatez= DZ;

surf(coordinatex, coordinatey, coordinatez, pressure, 'edgecolor', 'none')
xlabel('Coordinate X');
ylabel('Coordinate Y');
zlabel('Coordinate Z');
title ('Pressure VS Deformation');

[Walter Roberson]

Could you attach your data files?

But first make a small test: try

surf(coordinatex, coordinatey, coordinatez, pressure.', 'edgecolor', 'none')

[Andrea Hern{andez]

here

[Walter Roberson]

You have

a=load('presion.txt');
p=a(:,2);
p(21802:21810)=2.03;
m=length(p)/10;%number of rows

a is length 21802; you copy that and you specifically set up to entry 21810 of the result. Then you divide the length of that by 10, getting 2181 .

Note: the code that follows,

pressure=zeros(m,n);

%iteracion para formar matriz de 10 columna 

while i<=length(a)
    for k=1:n
        for j=1:m
        pressure(j,k)=p(i); 
        i=i+1;
        end
    end
end

could instead be written:

pressure = reshape(p, m, n);
pressure(length(a)+1:end) = 0;
pressure(21802) = 2.03;

This leads to the question of why you bothered with

p=a(:,2);
p(21802:21810)=2.03;

as p will never be used after it is copied into pressure and the entries from length(a)+1 to 21810 are going to be ignored. Unless, that is, that you are trying to account for the possibility that a is 21802 or longer and the entries starting from 21802 need to be set to 2.03 ??? If you are expecting variable length a, then what if it is more than 21810 long?

Anyhow, after that you have

b=load('deformacion.txt');
x=b(:,1); %x coordinate
y=b(:,2); %y coordinate
z=b(:,3); %z coordinate
x(21796:21800)=-5.29325;
y(21796:21800)=-7.553305;
z(21796:21800)=721.812683;

m=length(x)/10; %numer of rows

b is 21795 long, and you set the entries after that to 21800 to fixed values, and divide the length by 10, which is going to give you m = 2180 (unless the deformation file might have had more than 21800 entries.)

So now you have a problem: your pressure matrix is 2181 rows long, but your coordinate definitions are 2180 long, one row shorter.

How do you want to handle this situation?