terra: boundaries – R documentation

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boundaries

Detect boundaries (edges)

Description

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.

Usage

## 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`

Value

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

Examples

r <- rast(nrow=18, ncol=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)

terra

Spatial Data Analysis

v1.2-10

GPL (>= 3)

Authors

Robert J. Hijmans [cre, aut] (<https://orcid.org/0000-0001-5872-2872>), Roger Bivand [ctb] (<https://orcid.org/0000-0003-2392-6140>), Karl Forner [ctb], Jeroen Ooms [ctb] (<https://orcid.org/0000-0002-4035-0289>), Edzer Pebesma [ctb] (<https://orcid.org/0000-0001-8049-7069>)

Initial release

2021-05-12