read.asc {SDMTools} | R Documentation |
read.asc
and read.asc.gz
reads ESRI ArcInfo ASCII raster file
either uncompressed or compressed using gzip.
write.asc
and write.asc.gz
writes an asc object to a ESRI
ArcInfo ASCII raster file. The output can be either compressed or uncompressed.
These functions are faster methods based on the adehabitat import.asc and export.asc.
read.asc(file) read.asc.gz(file) write.asc(x,file) write.asc.gz(x,file)
file |
a character string representing the filename of the input/output file. The file extension should always be '.asc'. |
x |
an object of class 'asc' as defined in the adehabitat package |
Implements a faster version of import.asc or export.asc from the adehabitat package. In addition, files can be read in and written to in gzip compressed format.
Returns a raster matrix of the class 'asc' defined in the adehabitat package with the following attributes:
xll |
the x coordinate of the center of the lower left pixel of the map |
yll |
the y coordinate of the center of the lower left pixel of the map |
cellsize |
the size of a pixel on the studied map |
type |
either 'numeric' or 'factor' |
levels |
if type = 'factor', the levels of the factor. |
Jeremy VanDerWal jjvanderwal@gmail.com
#create a simple object of class 'asc' tasc = as.asc(matrix(rep(x=1:10, times=1000),nr=100)); print(tasc) #write out the raster grid file write.asc(tasc,'t.raster.asc') write.asc.gz(tasc,'t.raster.asc') #actually save file name as t.raster.asc.gz #read in the raster grid files tasc2 = read.asc('t.raster.asc') tasc3 = read.asc.gz('t.raster.asc.gz') #remove the temporary raster unlink(c('t.raster.asc','t.raster.asc.gz'))