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.