[R-sig-Geo] How to subset a spatial grid?

[Yong Li]

Dear All,

I want to subset a large spatial grid (2000*2000) into many smaller
grids for further processing in my simulation models. Could anyone do it
before and any tips will be highly appreciated?

Library(rgdal)
Map <- readGDAL("yong.img")  # one image from erdras imagine
Map$va <- Map$band1
Map$band1 <- NULL
????
Map1 <- a subset of Map$va based on selected cols and rows.
????......

Cheers

Yong Li