I did an interpolation of soil pH using 232 data points in geostatistical analyst with IDW, RBF and ordinary kriging. For all 3 methods, the range of pH values change (become smaller) after I export the geostatistical layers to raster. I understand that has something to do with the way values are calculated per cell in raster, but is there a way I could keep the pH range in the output raster?
The conversion of a geostatistical model to a raster will discretize the support (creating pixels). The value of the pixels will be defined at their center, so if the maximum/minimum is not at the center of a pixel, it will not be stored in the raster. If you want to be closer to the values, you will need to take a smaller pixel size.