rapp.Rd
Apply a function to a range of the layers of a SpatRaster that varies by cell. The range is specified for each cell with one or two SpatRasters (arguments first
and last
). For either first
or last
you can use a single number instead.
You cannot use single numbers for both first
and last
because in that case you could use app
or Summary-methods
, perhaps subset
ting the layers of a SpatRaster.
See selectRange
to create a new SpatRaster by extracting one or more values starting at a cell-varying layer.
# S4 method for SpatRaster
rapp(x, first, last, fun, ..., allyrs=FALSE, fill=NA,
clamp=FALSE, circular=FALSE, filename="", overwrite=FALSE, wopt=list())
SpatRaster
SpatRaster or positive integer between 1 and nlyr(x), indicating the first layer in the range of layers to be considered
SpatRaster or positive integer between 1 and nlyr(x), indicating the last layer in the range to be considered
function to be applied
additional arguments passed to fun
logical. If TRUE
, values for all layers are passed to fun
but the values outside of the range are set to fill
numeric. The fill value for the values outside of the range, for when allyrs=TRUE
logical. If FALSE
and the specified range is outside 1:nlyr(x)
all cells are considered NA
. Otherwise, the invalid part of the range is ignored
logical. If TRUE
the values are considered circular, such as the days of the year. In that case, if first > last the layers used are c(first:nlyr(x), 1:last). Otherwise, the range would be considered invalid and NA
would be returned
character. Output filename
logical. If TRUE
, filename
is overwritten
list with named options for writing files as in writeRaster
SpatRaster
r <- rast(ncols=9, nrows=9)
values(r) <- 1:ncell(r)
s <- c(r, r, r, r, r, r)
s <- s * 1:6
s[1:2] <- NA
start <- end <- rast(r)
start[] <- 1:3
end[] <- 4:6
a <- rapp(s, start, end, fun="mean")
b <- rapp(s, start, 2, fun="mean")
# cumsum from start to nlyr(x). return all layers
r <- rapp(s, start, nlyr(s), cumsum, allyrs=TRUE, fill=0)
# return only the final value
rr <- rapp(s, start, nlyr(s), function(i) max(cumsum(i)))