How can I get the equation of 3D interpolation?

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I'm trying to get the equation of 3D interpolation but i don't know how to do it. ¿How can I get the equation?
Currently I'm getting the values putting F(x,y) in the command window.
x = [470;470;470; 1000; 1000; 1000;];
y = [1;2;3; 1;2;3];
z = [-2.68;-0.98;-0.55;-1.42;0.36;0.8];
F = scatteredInterpolant(x,y,z);
[xq,yq] = meshgrid(470:1000,1:3);
vq1 = F(xq,yq);
hold on
legend('Sample Points','Interpolated Surface','Location','NorthWest')
Izan Segarra
Izan Segarra on 5 Mar 2019
I am making some measurements with differential probes. The results that we are obtaining are generating a lot of error of noise of the electrical installation. Then a study of these results has been made and it is possible to make a compensation to eliminate the noise, but it is necessary to interpolate all the obtained measurements and find an equation for its correction.
I have 4 data vectors:
  • Current vector = [1 2 3]
  • Impezanze vector = [470 1000]
  • Frequency vector = [8 9 10 11 12 15 16]
  • Error vector
The error vector contains the error for each impedance at each frequency and for each current, so I need to perform a 4D interpolation and get the equation to correct the measurement error.
I had started with a 3D interpolation and 6 points to understand how to perform the process. Could you help me get the equation?

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Accepted Answer

Matt J
Matt J on 5 Mar 2019
Edited: Matt J on 5 Mar 2019
I think you want griddedInterpolant instead:
F=griddedInterpolant({current,impedance,frequency}, Error);
Now just use it to evaluate the error at any combination of current, impedance, and frequency of interest,
You do not need to fit an equation to your original data.

More Answers (1)

darova on 5 Mar 2019
Try interp2 or fit


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