Export images from list of pixel images

Here's one way:

library(spatstat)

data(lansing)
rrisklan <- relrisk(lansing))

names(rrisklan)
[1] "blackoak" "hickory"  "maple"    "misc"     "redoak"   "whiteoak"

library(maptools)
## set up first grid, with first attribute "blackoak"
g <- as(rrisklan[[1]], "SpatialGridDataFrame")

names(g) <- "blackoak"

if (length(rrisklan) > 1) {  ## safety check
   for (i in 2:length(rrisklan)) {
     g[[names(rrisklan)[i]]] <- as(rrisklan[[i]], "SpatialGridDataFrame")[[1]]
  }
}

Compare:

plot(rrisklan)
spplot(g)

With the rgdal package you can now writeGDAL(g, "myfile.tif") but
whether your target can handle multi-attribute GeoTIFF is another
matter (the last few releases of ArcGIS use GDAL anyway so presumably
it would be fine).

Cheers, Mike.

Dear all,
I have a list of pixel images that I would like to export to in a raster
format, i.e. GRID, tif, etc, to be able to visualize them in ArcGIS/QGIS
but I am not sure how to convert them to SpatialGridDataFrame to be able to
export them as tif using writeGGAL. For example:

#########
data(lansing)
rrisklan <- relrisk(lansing))
#####################

The last yield a list of pixel images (rrisklan) with spatially varying
risk for each specie, how could I convert them to a appropriate format to
be able to export them as TIF.

Thanks,
Jose Funes
JHU

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Michael Sumner
Institute for Marine and Antarctic Studies, University of Tasmania
Hobart, Australia
e-mail: mdsumner at gmail.com