How to build a 2-D lookup table?

Hello,

I have measeared data in Excel. Inputs are x and y , according them an output z. All three have the dimensions (nx1). How can I make a 2-D lookup table with them? I tried and got a dimension-error. Eventually I have to make an interpolated matrix of my output z , but I do not know how. Does anybody have an idea? Thanks.

Answer 1

[Walter Roberson]

Unless there are repeated values forming an implicit grid, you should be using TriScatteredInterp or ScatteredInterpolant

[Hasan Dilek]

Thanks for your answer.

I tried with ScatteredInterpolant, and still could not bring my output to the right dimensions. As in the ScatteredInterpolant example see below, I need the output v in the dimension 200x200 , that is exactly my Problem. How can I do that?

xy = -2.5 + 5*gallery('uniformdata',[200 2],0);

x = xy(:,1);

y = xy(:,2);

v = x.*exp(-x.^2-y.^2);

F = scatteredInterpolant(x,y,v);

ti = -2:.25:2;

[xq,yq] = meshgrid(ti,ti);

vq = F(xq,yq);

...

[Walter Roberson]

Change the assignment to ti to be a vector of values with 200 entries. For example one version would be

ti = linspace(-2, 2, 200);

[Hasan Dilek]

Now it works:) Thank you !

[Derrick Gao]

awesome!!