Arguments
dat
a matrix with data suitable for plotting using the image function.
file
character string specifying the name and path of the ASCII raster output file.
xllcorner
the easting coordinate corresponding to the lower left hand corner of the matrix.
yllcorner
the northing coordinate corresponding to the lower left hand corner of the matrix.
cellsize
number, defining the size of each matrix cell.
na
scalar, defines null values in the matrix. NAs are converted to this value.