read.asciigrid returns the grid map read; either as
an object of class SpatialGridDataFrame-class or, if
as.image is TRUE, as list with components x, y and z.
Arguments
fname
file name
as.image
logical; if FALSE, a list is returned, ready to be
shown with the image command; if FALSE an object of
class SpatialGridDataFrame-class is returned
plot.image
logical; if TRUE, an image of the map is plotted
colname
alternative name for data column if not file name
proj4string
A CRS object setting the projection arguments of the Spatial Grid returned
x
object of class SpatialGridDataFrame
attr
attribute column; if missing, the first
column is taken; a name or a column number may be given
na.value
numeric; value given to missing valued cells in the
resulting map
...
arguments passed to write.table, which is used
to write the numeric data