scatteredInterpolant gives null matrix for collinear data . .

Hello, I want to interpolate scattered data (x,y,z). x and y are collinear (x and y = [0.05 0.1 0.15 0.20 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6] ).

When I use:

F = scatteredInterpolant(x, y, z);

[Xq, Yq] = meshgrid(x, y);

Zq = F(Xq, Yq);

I get empty Zq with following error : The underlying triangulation is empty - the points may be collinear.

Please help me on this.

[Walter Roberson]

Add a small random offset to x and y so that they are not colinear

[Parthu P]

Thanks a lot!

It worked very well.

Answer 1

[Image Analyst]

Use interp1() instead.

Answer 2

[Farough Rahimzadeh]

One trick you can do is to add one number to the end the array to remove the collinear correlation.

For example, my data is gravitational force at certain coordinates. Because I know gravitational force at 1e8 distance is roughphy equal to zero, I added one addition point of (1e8, -1e8, 0) to the data set to remove the linear correltion.

x = [1 2 3 4 5, 1e8];

y = [1 2 3 4 5, -1e8];

z = [1.8 1.2 2.2 1.9 1.2, 0];