You can set values of a Raster* object, when
i is a vector of cell numbers, a Raster*, Extent, or Spatial* object.
These are shorthand methods that work best for relatively small Raster* objects. In other cases you can use functions such as
calc and rasterize.
xa Raster* object
icell number(s), row number(s), Extent, Spatial* object
jcolumns number(s) (only available if i is (are) a row number(s))
valuenew cell value(s)