Expanding my interpolation grid for kriging in R

Question

I want to create an interpolation grid consisting of spatial data points to later use for kriging in R. I have been working in the sp and gstat packages. The code I am working with works, but my grid does not include all of the points and I want to expand it, but I can't seem to get it right.

The code I am working with is here (my data.frame is kr.data):

x.range <- as.integer(range(kr.data@coords[,1]))
y.range <- as.integer(range(kr.data@coords[,2]))
data.grd <- expand.grid(x=seq(from=x.range[1], to=x.range[2], by=0.5),  
y=seq(from=y.range[1], to=y.range[2], by=0.5))

coordinates(data.grd) <- ~x+y
gridded(data.grd) <- TRUE
plot(data.grd, cex=0.5)
points(kr.data, pch=1, col='red', cex=0.7)

I wanted to add the output to show the points concentrated in the lower right corner, off the grid, but I am new and not sure how to add this. Can anyone offer a suggestion on where to find help making a grid with spatial data or where to change my code? When I alter my code to expand the grid, my data points are no longer visible. I am new at working with spatial data in R.

Answer 1

Your truncation resulting from as.integer integer is probably cutting off the values at the high end of the ranges. Try instead:

x.range <- as.integer(range(kr.data@coords[,1])) + c(0,1)
y.range <- as.integer(range(kr.data@coords[,2])) + c(0,1)