MATLAB: Need to organize a large matrix into individual matrixes based on text files

dlmreadMATLABmatrix

I am trying to write a code that will produce a contour plot of many PIV Data points from DaVis .txt files.
The .txt file has 4 columns of data (X coordinates, Y coordinates, U velocity, V velocity). As of now I have the code reading this file with dlmread skipping the first row. I now need to take all X values and put them into their own matrix, as well for the Y, and U values to plot with pcolor.
As you can see in the .txt file Y values remain constant for 124 trials. I am trying to start a new column for X values everytime the Y values change. This should work out to a matrix with 124 columns and 173 columns for each Matrix, since there are 124 X,U,V values for each value of Y, and Y changes values 173 times.
I was intially trying reshape however I believe I will need a loop function to do this now.
type B00001.txt;
A=dlmread('B00001.txt', '',1,0);
X = reshape(A(:,1),173,124);
Y = reshape(A(:,2),173,124);
U = reshape(A(:,3),173,124);
V = reshape(A(:,4),173,124);
pcolor(X,Y,U); 
hold on
shading interp
colormap(jet);
colorbar

Best Answer

You should be fine, just reverse the order to (124,173). Elements are selected downward to fill the matrix. You can then transpose in you need 173x124 matrix.
X = reshape(A(:,1),124,173);
Y = reshape(A(:,2),124,173);
U = reshape(A(:,3),124,173);
V = reshape(A(:,4),124,173);
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