Converting RasterBrick object to im object in R

Question

During script execution I need to convert 'RasterBrick' to 'im' object. Package 'geostatsp' is supposed to do this job:

library(geostatsp)
myraster = raster(matrix(1:100,10,10), xmn=0,xmx=10,ymn=0,ymx=10)
class(myraster)
>[1] "RasterLayer"
>attr(,"package")
>[1] "raster"

myIm = as.im(myraster)
class(myIm)
>[1] "im"

But when I try it with real data I catch an error:

library(geostatsp)

b <- brick(some_file)
r <- raster(b)
class(r)
>[1] "RasterLayer"
>attr(,"package")
>[1] "raster"

bim <- as.im(r)
>Error in .local(x, ...) : 'x' has no values

What causes this?

Answer 1

The problem is that the default method for raster("RasterBrick") gives an empty layer. So, (as the error message states) your "r" has no data.

Here's a reproducible example that needs no knowledge of your file system, though it has nothing to do with the as.im method really.

library(geostatsp)
myraster = raster(matrix(1:100,10,10), xmn=0,xmx=10,ymn=0,ymx=10)

some_file <- "some_file.grd"

writeRaster(myraster, some_file)

b <- brick(some_file)
## here's the "fix"
r <- raster(b, layer = 1)

as.im(r)

See ?raster::raster for the "RasterBrick" method.