R language, problems with SpatialPixelsDataFrame

Question

(This question comes from https://stackoverflow.com/questions/40698369/r-language-problems-with-spatialpixelsdataframe?noredirect=1#comment68629240_40698369)

The following two scripts will generate a "SpatialPixelDataFrame" object:

# FIRST
library(rgdal)
elev.grid <- readGDAL("whatever.asc")
elev.grid <- as(elev.grid, "SpatialPixelsDataFrame")

# SECOND
library(raster)
library(SDMTools)
library(adehabitat)
elev.grid <- raster("whatever.asc")
elev.grid.asc <- asc.from.raster(elev.grid) 
elev.grid.SPDF <- asc2spixdf(elev.grid.asc)

However, the first one exceeds the capability of my computing resources when applying it to big (15000 x 16000) grids, and the second one generates an object which I can't use for some of my further analyses. For example, when I use it for krige purposes

x <- krige(V3~var, points, elev.grid) 

I get the following:

Error in model.frame.default(terms(formula), as(data, "data.frame"), na.action = na.fail) : invalid type (closure) for variable 'var'

Whether providing me a trick to bypass the memory/capability issue in the first case (preferably), or fixing the error generated by the second case please recommend.

Answer 1

A different way to obtain a spatial object useful for gstatpackage (krige() for Krigging) avoiding as(object,"Class") function, is convert it to SpatialPointsDataFrame and grid data.

Try this:

library(raster)
r <- raster("whatever.asc")
xy <- data.frame(xyFromCell(r, 1:ncell(r)))
v <- getValues(r)
xy[,"z"] <- v
coordinates(xy) <- ~x+y
gridded(xy) <- TRUE