Surfaces created with spline and IDW do not correspond with input point values

Discussion created by devlyn.hardwick on Jan 23, 2014
Latest reply on Apr 9, 2014 by devlyn.hardwick
I'm trying to compare the outputs of interpolated surfaces created using spline and IDW. Textbook definition of the spline method
says that the surface passes exactly through each sample point, whilst IDW will pass through none of the points. I realise that output cell size resolution has an impact on the interpolated surface and I can sort of understand why but I'm not sure why I'm not getting spline values that are exactly the same as the input points.