Hi all,
For some processing that I'm doing with raster data, I need to keep
track of cell centroid coordinate values, and I would like to do this in
terms of a set of reference rasters which hold cell values, x and y
coordinates, respectively, for the raster being analyzed. I can do this
(code below) but my question is: am I going about this in the most
efficient way? Here is what I'm doing (using a small test raster since
mine are humongous):
#get test raster
r <- raster(system.file("external/test.grd", package="raster"))
#make copies which will hold cell identifiers, x & y values
ry <- rx <- rc <- r
#define raster of cell numbers for the non-NA cells
rc[] <- seq(1:length(r))
## for some reason, this is not working: rc <- mask[rc,r]
## but this works fine:
rc[is.na(r)] <-NA
#assign coordinate values to corresponding rasters
ry[] <- yFromCell(rc, getValues(rc))
rx[] <- xFromCell(rc, getValues(rc))
# stack em up and view
s <- stack(r,rc,rx,ry)
names(s) <- c("values", "cell #", "x-coord", "y-coord")
plot(s)
So this works fine, but I have a feeling there are some shortcuts I'm
missing.
Thanks for guidance,
Jordan
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