How to surfc or surf a .mat file

Hi! I am trying to import a .mat file from a folder and trying to display through surf. But I am getting this error.

Answer 1

[Star Strider]

The error is clear --

imshow(imread('64C9C921-689D-4180-8EAD-7EE1126E5382.png'))

At least one of your data are vectors (it would nelp to have them). There are several ways to create matrices from vectors, depending on what the original data are. The easiest way to determine that is to plot all three vectors using the stem3 function and see what the result looks like. If the data appear to be gridded (regularly spaced, forming a sampled surface), use the reshape function to shape them into matrices. If they are not, then the vectors will have to be interpolated to matrices. The best way to do that is with the scatteredInterpolant function.

Regularly-spaced (gridded) vectors --

x = linspace(-5, 5, 10);
y = linspace(0, 11, 10);
[xm,ym] = ndgrid(x,y);
zm = exp(-(xm.^2 + (ym-5).^2)/10);

xyz = [xm(:) ym(:) zm(:)];                             % Vectors

figure
stem3(xyz(:,1), xyz(:,2), xyz(:,3), 'filled')

X = reshape(xyz(:,1), 10, []);
Y = reshape(xyz(:,2), 10, []);
Z = reshape(xyz(:,3), 10, []);

figure
surfc(X, Y, Z)
colormap(turbo)
colorbar

●

Randomly-spaced vectors --

x = randi([-500, 500], 15, 1)/100;
y = randi([0, 1100], 15, 1)/100;
[xm,ym] = ndgrid(x,y);
zm = exp(-(xm.^2 + (ym-5).^2)/10);

xyz = [xm(:) ym(:) zm(:)];                             % Vectors

figure
stem3(xyz(:,1), xyz(:,2), xyz(:,3), 'filled')

F1 = scatteredInterpolant(xyz(:,1), xyz(:,2), xyz(:,3))

F1 = 
  scatteredInterpolant with properties:

                 Points: [225×2 double]
                 Values: [225×1 double]
                 Method: 'linear'
    ExtrapolationMethod: 'linear'

x = linspace(-5, 5, 25);
y = linspace(0, 11, 25);
[X, Y] = ndgrid(x, y);
Z = F1(X, Y);

figure
surfc(X, Y, Z)
colormap(turbo)
colorbar

.

EDIT -- (20 Aug 2025 at 05:59)

Added example code.

.

Answer 2

[Walter Roberson]

The output of load() from a .mat file, is a structure, with one field for each variable that is loaded. You need to extract the necessary parts of the variable from the structure. For example,

cell1 = load('abcdef.mat').XData

if the variable was stored in XData in file abcdef.mat