Dear Julie,
This is one way to do that, using the raster package (under development):
install.packages("raster",
repos="http://R-Forge.R-project.org<http://r-forge.r-project.org/>
")
require(raster)
r <- rasterFromFile("d:/alt.asc", TRUE)
xy <- xyFromCell(r, 1:ncells(r))
xyv <- cbind(xy, values(r))
xyv[1:10,]
# To get rid of the NAs
xyv <- na.omit(xyv)
xyv[1:10,]
On Thu, Jan 15, 2009 at 1:01 AM, Juliane Struve
<juliane_str...@yahoo.co.uk>wrote:
> Dear list,
>
> I am trying to read ArcGIS raster data sets into R after converting them
> into ASCII .txt file. The text file I am trying to read contains
>
> ncols 250
> nrows 276
> xllcorner 344147.19411119
> yllcorner 3024657.6122834
> cellsize 0.19970250725746
> NODATA_value -9999
>
> in the first lines followed by a grid of values that are either -9999 or 1.
>
> I have used read.table("myfile.txt") which yields this (first 10 lines).
>
>
> V1 V2
> 1 ncols 2.500000e+02
> 2 nrows 2.760000e+02
> 3 xllcorner 3.441472e+05
> 4 yllcorner 3.024658e+06
> 5 cellsize 1.997025e-01
> 6 NODATA_value -9.999000e+03
> 7 -9999 -9.999000e+03
> 8 -9999 -9.999000e+03
> 9 -9999 -9.999000e+03
> 10 -9999 -9.999000e+03
>
> I would like to have the data as a table with coordinates for each cell and
> the actual value.
>
> Could somebody advise me which function I should use ?
>
> Many thanks,
>
> Juliane
>
>
>
>
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