how can i compare 3 different columns of an Excel sheet with contourf plot in Matlab GUI

Hello all, nowadays i am making a GUI through matlab designer to compare different parameters, i have to compare 3 different columns of Excel sheet with contourf plot. And I am getting error of 'Error using contourf (line 57) Z must be at least a 2x2 matrix.'

Thank you all in advance, please help me out, i am stucked with my task.

here is my code:

Parameter = readmatrix('GUI1.xlsx');

Parameter1 = Parameter(51*1);

Parameter2 = Parameter(51*2);

Parameter3 = Parameter(51*3);

Parameter4 = Parameter(51*4);

if (strcmp(app.XAchseParameterDropDown.Value,'DE'))

X = Parameter1;

elseif (strcmp(app.XAchseParameterDropDown.Value,'DI'))

X = Parameter2;

elseif (strcmp(app.XAchseParameterDropDown.Value,'DrE'))

X = Parameter3;

else

X = Parameter4;

end

if (strcmp(app.YAchseParameterDropDown.Value,'DE'))

Y = Parameter1;

elseif (strcmp(app.YAchseParameterDropDown.Value,'DI'))

Y = Parameter2;

elseif (strcmp(app.YAchseParameterDropDown.Value,'DrE'))

Y = Parameter3;

else

Y = Parameter4;

end

if (strcmp(app.ZAchseParameterDropDown.Value,'DE'))

Z = Parameter1;

elseif (strcmp(app.ZAchseParameterDropDown.Value,'DI'))

Z = Parameter2;

elseif (strcmp(app.ZAchseParameterDropDown.Value,'DrE'))

Z = Parameter3;

else

Z = Parameter4;

end

contourf(app.UIAxes,X,Y,Z)

[Voss]

Can you attach the relevant Excel file (which is called 'GUI1.xlsx' in this code)?

Answer 1

[Cris LaPierre]

A contour plot is created from a matrix (Z data; see here). You must be giving it a vector, causing the error message you see.

You can learn more and see examples in the contourf documentation page.

% Works
x = -2:0.2:2;
y = -2:0.2:3;
[X,Y] = meshgrid(x,y);
Z = X.*exp(-X.^2-Y.^2);
contourf(X,Y,Z,'ShowText','on')

% recreates the error you are seeing
x = -2:0.2:2;
y = -2:0.2:3;
[X,Y] = meshgrid(x,y);
Z = X.*exp(-X.^2-Y.^2);
contourf(X,Y,Z(:),'ShowText','on')

Error using contourf (line 57)
Z must be at least a 2x2 matrix.

How you convert your column data to a matrix is going to depend on your data. It's very difficult to answer that question withough more information.

[Darshil Pragneshbhai Trivedi]

so i have a 4 colums and 51rows in a datasheet in excell. which 4 colums i have to compare with each other.

[Cris LaPierre]

I think you'd have to tell us that. I'm not sure how we would know.

Generally speaking, your X and Y values will be inputs (independent variables) and Z will be your output or response (dependent variable).