Input coordinates cannot be complex.

I am trying to calculate the surface area of a plot generated using surf. I am using the function surfarea attached. I keep getting the error Input coordinates cannot be complex when executing griddata. None of the coordinates in the file are complex. The file is too large to attach so I am including an extract image. The file is downloadable at https://we.tl/t-mfKxV2RFQ3 . Can anyone indicate a potential reason please?

clc;
clear variables;

T=readtable('C:\Users\CT\Desktop\Matlab Question\Surface.dat');

 x=T(:,1);
 y=T(:,2);
 z=T(:,3);

[X,Y] = meshgrid(0:1:2455, 0:1:1848);
Z  = griddata(x,y,z,X,Y);
    
h = surf(X,Y,Z);
[totalArea] = surfarea(h);
shading interp;
xlabel('x'), ylabel('y'), zlabel('z'),colorbar
title(sprintf('Total surface area: %.2f', surfarea(h)));
view(60,30);

saveas(h, 'C:\Users\CT\Desktop\Matlab Question\Surface.png');

Update:

The code works fine when using

T=xlsread('C:\Users\CT\Desktop\Matlab Question\Surface.xlsx', 1);

instead of readtable. However I cannot import data from Excel as the original data file contains 10.9 million rows.

Answer 1

[Star Strider]

If you can read the entire file with readtable and you simply want the data in the table, consider using the table2array function to convert your table columns to a double array.

I have no idea what the problem could be with complex values and griddata, especially if your code works with xlsread.

[Christabelle Tonna]

This actually solved it for me. Thanks a lot!

[Star Strider]

As always, my pleasure!