And here is my script file run in both Octave and Matlab.
data = "" ; % read file
x = data(:,1);
y = data(:,2);
z = data(:,3);
% Grid
%x0 = min(x) ; x1 = max(x) ;
%y0 = min(y) ; y1 = max(y) ;
%N = 10 ;
%x2 = linspace(x0,x1,N) ;
%y2 = linspace(y0,y1,N) ;
%[X,Y] = meshgrid(x2,y2) ;
[X,Y] = meshgrid(sort(x),sort(y));
Z = griddata(x,y,z,X,Y,'linear');
figure (1)
contourf(X,Y,Z);
colormap ('jet')
colorbar
figure (2)
meshc(X,Y,Z)
colormap ('jet')
colorbar
figure (3)
contour(X,Y,Z);
%meshc(X,Y,Z)
colormap ('jet')
colorbar
xlabel ('Vds')
ylabel ('Ids(mA/mm)')
title ('S11 VAEerr')