SURF plot: Data dimensions must agree

I am trying to plot the magnetic field on a rectangular surface (having x and y coordinates). Hence i have a total of 3 values x,y and B (magnetic field). I have tried plotting the surface plot using normal and transposed datasheet in excel but both of them give me the same data dimensions error. Please help me withi this. I am using the following code till now:

dataset=xlsread('import.xlsx');
x = dataset(:,1);
y = dataset(1,:) 
Z = dataset(2:end,2:end)
surf(x,y,Z)   

Please see the attached image for clarification.

thank you

Answer 1

[Walter Roberson]

dataset=xlsread('import.xlsx');
x = dataset(2:end,1);
y = dataset(1,2:end);
Z = dataset(2:end,2:end);
surf(x, y, Z.', 'edgecolor', 'none')

[Azeem Singh Kahlon]

Thank you so much and I probably understand the logic now that the value on the top left hand corner of the excel sheet is not included in either X or Y and hence would be inconsistent with the dimensions of Z.

Also, thank you for answering so promptly.

[Walter Roberson]

Notice also the transpose I do on Z.

[Azeem Singh Kahlon]

yes I see that (Z.). However, I do not understand its significance because "Z." and "Z" give the same results.

Thank you once again

Answer 2

[Hélène Parisot-Dupuis]

Hello,

I have the kind of problem with my code and I don't understand why:

for it=1:2
    xt(it,1)=it
    for jt=1:3
        yt(1,jt)=jt
        zt(it,jt)=it+(jt-1)
    end
end

xt = 1

yt = 1

zt = 1

yt = 1×2

1 2

zt = 1×2

1 2

yt = 1×3

1 2 3

zt = 1×3

1 2 3

xt = 2×1

1 2

yt = 1×3

1 2 3

zt = 2×3

1 2 3 2 0 0

yt = 1×3

1 2 3

zt = 2×3

1 2 3 2 3 0

yt = 1×3

1 2 3

zt = 2×3

1 2 3 2 3 4

figure;
surf(xt,yt,zt,'EdgeColor', 'None', 'facecolor', 'interp');

Error using surf
Data dimensions must agree.

view(2);
colormap(jet(256));
c = colorbar;

Could you help me to find my error please?

Thanks in advance!

[Walter Roberson]

Remember that rows of an array correspond go y and columns correspond to x . When your x and y are vectors, your z array needs to be length(y) by length(x)

for it=1:2
    xt(it,1)=it
    for jt=1:3
        yt(1,jt)=jt
        zt(it,jt)=it+(jt-1)
    end
end

xt = 1

yt = 1

zt = 1

yt = 1×2

1 2

zt = 1×2

1 2

yt = 1×3

1 2 3

zt = 1×3

1 2 3

xt = 2×1

1 2

yt = 1×3

1 2 3

zt = 2×3

1 2 3 2 0 0

yt = 1×3

1 2 3

zt = 2×3

1 2 3 2 3 0

yt = 1×3

1 2 3

zt = 2×3

1 2 3 2 3 4

figure;
surf(xt,yt,zt.','EdgeColor', 'None', 'facecolor', 'interp');
view(2);
colormap(jet(256));
c = colorbar;

[Walter Roberson]

There are two competing standards for array notation.

1. When using x and y coordinates, western mathematics tends to put the x first (as rows) and then the y (as columns) -- so in terms of standard Cartesian coordinates, horizontal distance first then vertical distance
2. When using tables of data, such as a table of costs or a table of trigonmetric values, western mathematics tends to refer to row first and then column -- for example you would look on the row for 1983 and then the column for month -- so vertical distance listed first and then horizontal distance

Any programming language that choses one particular representation (rows mean horizontal distance, rows mean vertical distance) will fail on the other one. So the problem is not a "bug" in MATLAB, or a "mis-design": the problem is competing conventions that cannot both be satisfied.

[Hélène Parisot-Dupuis]

Thank you for your answer and these clarifications!