On Thu, Jun 17, 2010 at 7:27 PM, Grant Gillis <grant.j.gil...@gmail.com> wrote:
> grid1 <- readAsciiGrid("C:\\junk\\grid1.asc")
> grid2 <- readAsciiGrid("C:\\junk\\grid2.asc")
>
> After this no luck with the "mean" command
These things are SpatialGridDataFrames and can be 'cbind'ed together:
> gAll = cbind(grid1,grid2)
> spplot(gAll)
now compute the row means and add them to the data frame:
> gAll$mean = apply(g...@data[,1:2],1,mean)
> spplot(gAll)
Just to make sure it was doing the right thing I made some test data:
> g...@data[,1]=1:100
> g...@data[,2]=100:1
> gAll$mean = apply(g...@data[,1:2],1,mean)
> spplot(gAll)
- which shows me two ramps in opposite directions and a very flat
mean, with value:
> g...@data[,3]
[1] 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5
[16] 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5 50.5
How's that? It probably only works if the grids have the same spatial
basis. If you've really got many of these, then write a loop.
Barry
_______________________________________________
R-sig-Geo mailing list
R-sig-Geo@stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
