2D Spline Interpolant problems

[weizbox]

I need to impterpolate a 2D array, and it seems to work somtimes, but somthing not as well. I seem to get a "tail" at the start or end of the interpolation. I included an attachment of a picture of what happens. Can anyone tell me why this is happening with my data only occationaly.

Thanks,
-Mark

[Dr._Imad]

You may be extrapolating instead of interpolating. Spline interpolation only interpolates. If you have a point outside the input (x data), spline interpolation won't do it