All 3 methods (IDW, Spline, Kriging) crash ArcMap. I'm running 9.3.1 & haven't run Spatial Analyst in a couple of months. I'm trying to create an elevation surface from elevation point data. I've used these same data sets n the past with no problems. I accept the default settings. Here's the weird part - when I use the same data sets in Geostatistical Analyst, they work (I've tested IDW & Kriging). Don't they run the same code to do the modelling?