I did notice that, but there was no ==line== section in the doc I have. Is
my package outdated ?
No, there were no additional arguments for lines specifically. There is one
now (cellnumbers) in the R-Forge version (1.8-6).
The values are first in row order, and then in column order. Not in the
order of the coordinates of the line(s).
I'm trying to think of a way to order these. Do you see a simple solution ?
I'm finally doing a profile from a raster using a line.
Below I show how -- I think -- you can order the values such that they
follow the line.
library(raster)
r <- raster(matrix(1:20, nrow=4))
l <- SpatialLines(list(Lines(list(Line(list(x=c(0, 1), y=c(0, 1)))), ID=1)))
plot(r, asp=1); lines(l)
a <- extract(r, l, cellnumbers=T)[[1]]
rc <- rowColFromCell(r, a[,1])
b <- cbind(rc, value=a[,2])
#order top to bottom
b[order(-b[,1], b[,2]), 3]
#order bottom to top
b[order(b[,1], -b[,2]), 3]
# or
rev( b[order(-b[,1], b[,2]), 3] )
--
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