2D plot of deformation data

Hi,

I have txt file with information of x and y coordnates and c as color data and u,v as defromation data which is for displacment.

I want to plor the 2D of the displacment with its color. what I was able to do is plot the data with no defromation, displacment, as shown in the image

my code is after I load the data.

x = data(:,1);
y = data(:,2);
c = data(:,3);
U = data(:,4);
V = data(:,5);
n = 500
[X, Y] = meshgrid(linspace(min(x),max(x),n), linspace(min(y),max(y),n));
ColorData = griddata(x,y,c,X,Y);

pcolor (X,Y,ColorData);

When I used the U and V I got this image

[Mathieu NOE]

hello

can you share your data file ?

[Sara]

Hi,

I attached a data similar to the data used to the plot in my question but same with different deformation

[William Rose]

@Sara,

[edit: fix typos and change two lines from text to code]

You say "When I used the U and V I got this image", but the code you posted does not use U and V. It uses the c array for color. If you attach array "data" array as a file, others could see. Are the values of c (which are given, not calculated in your code) derived from U and V, or are the c values independent of U and V? If they are independent, and if you are interested in using color to represent the displacements that are in the U and V vectors, then you can ignore the c values.

Since displacement includes both U and V components, you have to decide how you want to combine them for plotting purposes. Two obvious options (among many possible options) are

d=sqrt(U.^2+V.^2);

or

d=max(U,V);

Then you use d to compute the ColorData:

ColorData = griddata(x,y,d,X,Y);

and plot as before.

[Sara]

what I ment is switching the code from

ColorData = griddata(x,y,c,X,Y);

to

ColorData = griddata(U,V,c,X,Y);

but I will try to do your code in my code and see what will happen

Thank you

[William Rose]

@Sara,

You said you wante d to switch the code from

ColorData = griddata(x,y,c,X,Y);

to

ColorData = griddata(U,V,c,X,Y);

I don;t think this will do what you want, because griddata is a 2D interpolation routine. In the first form, it assume you measured c at points x and y, and it interpolates those measurements to the gird X,Y. But U,V are not measurement locations - they are measured values.

Answer 1

[Mathieu NOE]

hello again

basically used the same code for U and V and got these 3 plots

for ColorData

for U

for V

code :

data = readmatrix('data.txt');

x = data(:,1);
y = data(:,2);
c = data(:,3);
u = data(:,4);
v = data(:,5);

n = 500;
[X, Y] = meshgrid(linspace(min(x),max(x),n), linspace(min(y),max(y),n));
ColorData = griddata(x,y,c,X,Y);
U = griddata(x,y,u,X,Y);
V = griddata(x,y,v,X,Y);

figure(1), 
pcolor(X,Y,ColorData);
shading('interp')
colormap('jet');

figure(2), 
pcolor(X,Y,U);
shading('interp')
colormap('jet');

figure(3), 
pcolor(X,Y,V);
shading('interp')
colormap('jet');