boundaries.Rd
Detect boundaries (edges). Boundaries are cells that have more than one class in the 4 or 8 cells surrounding it, or, if classes=FALSE
, cells with values and cells with NA
.
# S4 method for SpatRaster
boundaries(x, classes=FALSE, inner=TRUE,
directions=8, falseval=0, filename="", ...)
SpatRaster
logical. If TRUE
, "inner" boundaries are returned, else "outer" boundaries are returned
character. Logical. If TRUE
all different values are (after rounding) distinguished, as well as NA
. If FALSE
(the default) only edges between NA
and non-NA
cells are considered
integer. Which cells are considered adjacent? Should be 8 (Queen's case) or 4 (Rook's case)
numeric. The value to use for cells that are not a boundary and not NA
character. Output filename
options for writing files as in writeRaster
SpatRaster. Cell values are either 1 (a border) or 0 (not a border), or NA
r <- rast(nrows=18, ncols=36, xmin=0)
r[150:250] <- 1
r[251:450] <- 2
bi <- boundaries(r)
bo <- boundaries(r, inner=FALSE)
bc <- boundaries(r, classes=TRUE)
#plot(bc)