1. ## interpolate measured data

I have a measured data set (x & y are inputs, z is the result at those measures):

x y z
0.036802 0.004908 0.07158
0.036802 0.022135 0.10095
0.130886 0.004908 0.09627
0.130886 0.022135 0.12560

I would like a formula for interpolation, to predict z for all input conditions x & y (within bounds), for example when x=0.0875 & y=0.0066.

I have tried some some formulas, but nothing is predicting with much accuracy.

Thanks for any help
J

2. Originally Posted by jhasting
I have a measured data set (x & y are inputs, z is the result at those measures):

x y z
0.036802 0.004908 0.07158
0.036802 0.022135 0.10095
0.130886 0.004908 0.09627
0.130886 0.022135 0.12560

I would like a formula for interpolation, to predict z for all input conditions x & y (within bounds), for example when x=0.0875 & y=0.0066.

I have tried some some formulas, but nothing is predicting with much accuracy.

Thanks for any help
J
The four data points you have there may be interpolated exactly with a function of the form $\displaystyle z = a + bx + cy + dxy$. Plug in the four data points and solve for a, b, c, d.