Another way is to use the coercion methods in maptools (these are considered additional to the basics provided by sp, since they provider converters between classes in other packages):
library(maptools) as(Im, "SpatialGridDataFrame") In terms of the data the result is identical to Rolf's method, though various attributes will not be. Cheers, Mike. On Tue, Jul 12, 2011 at 1:30 PM, Rolf Turner <r.tur...@auckland.ac.nz> wrote: > > This is definitely a case of the blind leading the blind, but I thought I'd > chip > in anyway. > > Let "Im" be your pixel image. Do: > > xy <- as.matrix(as.data.frame(raster.xy(as.owin(Im)))) > v <- lookup.im(Im,xy[,1],xy[,2]) > A <- SpatialPixelsDataFrame(points=xy,data=data.frame(v)) > B <- as(A,"SpatialGridDataFrame") > > Then "B" is an object of class "SpatialGridDataFrame" which ***may*** be > what > you need. I can't really tell, since I don't understand > SpatialGridDataFrames. > > The foregoing is kludgey, almost surely sub-optimal, and quite possibly > wrong ..... > But there's a chance it will be of some use to you. > > cheers, > > Rolf Turner > > On 12/07/11 10:54, Honey-Marie de la Giroday wrote: >> >> Dear All, >> >> I have a pixel image (im) I received as a .RData file. I need to >> export this pixel image from R in a file format that can be imported >> into Arcview 9.x (e.g., .e00 or ascii). >> >> Below is some of the code that I have been trying to use. I have >> reviewed the manuals for rgdal, maptools, sp, and spatstat packages >> but have been unable to find another approach to converting the pixel >> image to an Arcview raster dataset. Please note that I have also >> searched the R-sig-geo archives and was unable to find this covered >> elsewhere. >> >> "#load spatst package >> library(spatstat) >> >> #load file with model data >> load(file="C:/bestmodel2004.RData") >> >> #Plot best model data for 2004 >> plot(bestmodel2004) >> >> #Examine attributes of pixel image >> attributes(bestmodel2004) >> $names >> [1] "v" "dim" "xrange" "yrange" "xstep" "ystep" "xcol" "yrow" >> [9] "type" "units" >> >> $class >> [1] "im" >> >> #Load sp package >> library(sp) >> >> #Coerce bestmodel2004 (pixel image) to SpatialGridDataFrame >> #......how do I do this?...... >> >> #Output to Acrview = write.asciigrid(x, fname, attr=1, na.value=-9999..... >> #x=SpatialGridDataFrame >> #fname=filename >> write.asciigrid" >> >> Thank you for your time, and please let me know if I need to provide >> further information. >> >> Sincerely, >> >> >> >> H.M.C de la Giroday >> >> _______________________________________________ >> R-sig-Geo mailing list >> R-sig-Geo@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > -- Michael Sumner Institute for Marine and Antarctic Studies, University of Tasmania Hobart, Australia e-mail: mdsum...@gmail.com _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
