Here is a code fragment that fits a plane to the 3D data in the file, and plots the 3D data from the file as well as the points on the best-fit plane.
load points.mat;
%skip row 1 since fintcp(1)=NaN
fintcp=fintcp(2:end); x1cp=x1cp(2:end); x2cp=x2cp(2:end);
mdl=fitlm([x1cp;x2cp]',fintcp'); %fit linear model
d1=(-4:0.5:4); %mesh x-coordiates
d2=(-3:0.5:3); %mesh y-coordinates
[X,Y]=meshgrid(d1,d2); %create X,Y meshes, 13x17
%Next lines use the linear model to predict z-values at the mesh points
Xv=reshape(X,[],1); Yv=reshape(Y,[],1); %reshape meshes into vectors
Xall=[ones(size(Xv)),Xv,Yv]; %221x3 matrix for linear prediction
zpred=Xall*mdl.Coefficients.Estimate; %vector: 221 predicted values
zpred=reshape(zpred,size(X)); %reshape vector to mesh
%plot results
figure
plot3(x1cp,x2cp,fintcp,'r', 'LineWidth',2)
xlabel('X'); ylabel('Y'); zlabel('Z'); hold on; grid on
surf(X,Y,zpred)
After you run this, you can rotate the 3D plot by clicking on the 3D rotate icon at the top, then click and drag in the plot.
Try it. Good luck.
