Read a 3D matrix from Excel file

I have an Excel file of multiple rows and columns. I want to plot the entire file as a 3D plot. The first row is X and the First column is Y. I have tried to read X,Y and Z with the below codes, but I faild.I want to insert this data into a 3D matrix, in which I could do some calculations on that and then plot it. How can I insert this Excel file into a 3D matrix? and How can I plot it? I have also attached the Excel file. Thanks

x=sample(1,2:22)
y=sample(2:102,1)
xSize=length(x);
ySize=length(y);

for i=1:xSize
    for j=1:ySize
        
        xP(i)=x(i);
        yP(j)=y(j);
        zP(i,j,j)=sample((i+1),(j+1))
    end
end

[Geoff Hayes]

@Behrad Ze - where is the code to read the file? Or are you missing that code?

[Behrad Ze]

I am loading the code by selecting the rows and columns with matlab interface,and then importing them as a matrix.

[dpb]

What's the third dimension supposed to be/represent?

You apparently have an XY plane with the X,Y coordinates at the top and left side of a 2D array -- simply

Z=readmatrix('sample.csv');             % return the whole 2D array
X=XYZ(1,2:end);                         % pick first row for X
Y=XYZ(2:end,:);                         % and first column for Y
X=Z(2:end,2:end);                       % now save the response variable only for Z

After this to plot a surface or whatever, look at surf() and friends; later releases of MATLAB don't require the explicit construction of the XY grid points via meshgrid as did earlier.

But, there isn't a Z direction in the data to use as an index to a plane to create a 3D array; don't know what your trying to do there...

[Voss]

The data in sample.csv is a 101-by-21 matrix (not counting the first row and first column, which are X and Y indices). How would you like to manipulate a 101-by-21 matrix into a 3D matrix, i.e., what size should the 3D matrix be?

101-by-3-by-7?

101-by-7-by-3?

101-by-1-by-21?

101-by-21-by-1? (It already is this.)

3-by-7-by-101?

3-by-101-by-7?

etc.

[Behrad Ze]

All the cells except the first row and the first column are my Z direction.I have actually 21*101 values for the Z direction.

[Behrad Ze]

I am quite new to Matlab. I have plotted it using Origin,but I need to manipulate it using Matlab.I am not sure if it makes sense to use 3d matrix in this case.I have 21 X values, 101 Y values, and 21*101 Z values.I am really puzzled. What could the best option to store these values? Thank You

Answer 1

[Voss]

I think a 2D matrix is the way to go, since you have one value for each (x,y) point.

Here are some ways you might visualize your data. All of these ways create a surface object:

sample = readmatrix('sample.csv');
x=sample(1,2:end);
y=sample(2:end,1);
data = sample(2:end,2:end);

figure();
surf(x,y,data);
colorbar();

Then the same surface viewed from above:

figure();
surf(x,y,data);
colorbar();
view([0 90]);

Another way to do the same thing:

figure();
pcolor(x,y,data);
colorbar();

[Behrad Ze]

Thanks for your answer. It worked!