"For all interpolation methods other than "v4", the output vq contains NaN values for query points outside the convex hull of the sample data. The "v4" method performs the same calculation for all points regardless of location."
Using "v4", you will see points where you expected to originally:
N = 20; %vs e.g.100
x = [8.53315129274914,9.30925339785209,8.53315129274914,9.30925339785209,9.30925339785209,9.30925339785209,9.30925339785209,4.45216152440796,3.79261956232135,3.79261956232135,17.0677590031963,17.0677590031963,4.09601048577567,5.68892934348203];
y = [1.32520094900129,1.32154631465502,1.19462692171560,1.24730173230503,1.10676794920524,1.09225969341119,0.815136578214699,0.757268342808360,1.01606958162158,0.942815599343300,0.675121536953220,0.693923408467932,1.15323471371613,1.62262286756171];
xvec = linspace(min(x), max(x), N);
yvec = linspace(min(y), max(y), N);
[X, Y] = meshgrid(xvec, yvec);
data = [53.3523658491640,73.0221175190515,66.4448159677658,53.0481929355336,34.9019870840489,27.0340993276701,388.109339785705,341.752595986306,561.738449969976,481.741285644030,93.8209397136714,36.7262731504483,538.496713957595,820.698548835111];
Z = griddata(x,y,data,X,Y,"v4");
figure
surf(X,Y,Z)
view(2)
hold on
plot3(x,y,data,'r.','MarkerSize',20)
