What would be a best interpolation method to get test data for a specific temperature?

I have 4 columns of test data (Temp, X, Y, Z). I want to create slices of data (X,Y,Z) for temperatures not collected (0, 40, 100). Each temperature would create a 3d dataset that I would want to graph as a surface. My data does not have the exact temperatures so how can I interpolate the data to get the data I am after?

My data is for each temp (-20, 60, 120, 160), X varried from 0 to 1 and Y varried from 1000 to 10000 and Z was measured. I would like to know how I can create the X, Y and Z data for different temperatures with X and Y varrying the same way.

Also for each temperature, X and Y do not varry the same. They are not gridded, One test run X might be 0.05, 0.34, 0.68 etc... whereas the next time it might be 0.02, 0.28, 0.57 etc...

Answer 1

[Star Strider]

I would just use interp1 —

TestData = sortrows(randi([0 200], 15, 4),1)

TestData = 15×4

15 148 72 99 40 97 95 190 43 162 43 162 57 107 19 197 66 145 46 174 81 119 150 111 82 7 164 12 84 57 200 155 95 190 137 89 105 2 123 49

InterpTemps = [0 40 100];
Interp_234 = interp1(TestData(:,1), TestData(:,2:4), InterpTemps, 'linear','extrap')

Interp_234 = 3×3

178.6000 58.2000 44.4000 97.0000 95.0000 190.0000 96.0000 130.0000 69.0000

Result = [InterpTemps(:) Interp_234]

Result = 3×4

0 178.6000 58.2000 44.4000 40.0000 97.0000 95.0000 190.0000 100.0000 96.0000 130.0000 69.0000

.

[Jason Burke]

Thanks for this. I won't have just one data row for each temperature. There will be many. I tried this and got an error saying the grid vectors must contain unique points.