On Tue, 22 Jan 2008, Jarek Jasiewicz wrote:
Hi?
subset(spGRID, raster==1) or subset(spGRID, data$raster==1)
Can I do this or something similar??
i.e I'd like to avoid to convert raster to regular data.frame and use subset
on dataf.rame due to long time of conversion
Hi,
There is no guarantee that the output is going to be a full grid, so I
suggest casting to SpatialPixelsDataFrame first and subsetting that:
library(sp)
data(meuse.grid)
coordinates(meuse.grid) <- c("x", "y")
gridded(meuse.grid) = TRUE
fullgrid(meuse.grid) = TRUE
summary(meuse.grid)
o1 <- as(meuse.grid, "SpatialPixelsDataFrame")
o2 <- o1[o1$ffreq == 1,]
summary(o2)
Hope this helps,
Roger
tahnx
Jarek
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Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
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