library(raster)
library(kriging)

W <- shapefile('Mg_region.shp')

x <- coord_na_removed[,2]
y <- coord_na_removed[,1]
z <- stations_fma_alt_jja

data <- data.frame(x,y,z)
coordinates(data) <- ~x+y

# Generate Grid
grd <- makegrid(W, n = 10000)
colnames(grd) <- c('x','y')
outline <- W@polygons[[1]]@Polygons[[1]]@coords
require(splancs)
W_grid <- grd[inout(grd,outline), ]
gridded(W_grid) <- ~x+y

krig <- autoKrige(z~1, data, W_grid)
plot(krig)