Interpolating data from a table

Hello,

I'm trying to get the interpolated Cl and Cd from this table. For example, say for -173.2 AOA, I want to find out the corresponding Cl & Cd. The file here is an excel file and I have imported them into matlab and named the variable naca which is the size of 395*4. I have also tried interp1 function to interpolate.

For example,

I tried, interp1(naca.AOA, naca.Cl, -173.2);

The error it gives out is- "Error using griddedInterpolant

The sample points must be finite.

Error in interp1 (line 170)

F = griddedInterpolant(X,V(:,1),method);"

Any help regarding this would be really appreciated.

Answer 1

[Cris LaPierre]

Works here. Perhaps try clearing your workspace and then rerunning your code.

AOA = (-180:1:-167)';
Cl = sort(rand(size(AOA))-0.15);
Cd = sort(rand(size(AOA)));
naca=table(AOA,Cl,Cd)

naca = 14x3 table
    AOA         Cl           Cd   
    ____    __________    ________

    -180      -0.14264    0.068609
    -179      -0.10548     0.10965
    -178      -0.05547     0.12092
    -177     -0.051742     0.18885
    -176    -0.0049866     0.49856
    -175      0.027617     0.50889
    -174        0.0449      0.5568
    -173       0.11746     0.62728
    -172       0.14203     0.67654
    -171       0.29605     0.68496
    -170        0.3297     0.87587
    -169       0.75624     0.88073
    -168       0.77464     0.91418
    -167       0.81968     0.91765

interp1(naca.AOA,naca.Cl,-173.2)

ans = 0.1030

[Rifat Ibn Azad Tanim]

Hi,

Thank you so much for replying. Turns out I couldn't do it because I had NaNs in the table. I had to get rid of the NaNs to get it working. Any idea as to how to get around those NaNs? Anyway, for now, it's working. Thank you very much again.

[Cris LaPierre]

You could use the rmmissing and/or fillmissing functions to handle NaNs.