Probably this question has been answered before, but I did a search and found no clues. I want to interpolate Temperature surface from a set of stations. I have a DEM, and UTMx, UTMy for each station. I made a linear multiple regression on temperature against UTMx, UTMy and elevation, ans now I have a formula. Then I calculate the residuals for each station and I am told to interpolate (kriging) with these residuals and then add this to the surface that results from the linear regression. My question is... If I only had made the regression con the elevation model, I will use the Raster calculator and make the "no-residuals" surface to wich I will add the interpolated residual surface. But I also have latitude and longitude. Should I create a raster for the longitude and a raster for the latitudes? Remember that I only have the coordinates for the stations, and are points.