boundaries function

Detect boundaries (edges)

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 signature 'SpatRaster'
boundaries(x, classes=FALSE, inner=TRUE, 
         directions=8, falseval=0, filename="", ...)

Arguments

• x: SpatRaster
• inner: logical. If TRUE, "inner" boundaries are returned, else "outer" boundaries are returned
• classes: 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
• directions: integer. Which cells are considered adjacent? Should be 8 (Queen's case) or 4 (Rook's case)
• falseval: numeric. The value to use for cells that are not a boundary and not NA
• filename: character. Output filename
• ...: options for writing files as in writeRaster

Returns

SpatRaster. Cell values are either 1 (a border) or 0 (not a border), or NA

See Also

focal, patches

Examples

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)