pitfinder: Find pits (depressions with no outlet)

In terra: Spatial Data Analysis

Find pits (depressions with no outlet)

Description

find pits (depressions with no outlet) using a flow direction raster, to support the delineation of catchments.

Usage

## S4 method for signature 'SpatRaster'
pitfinder(x,pits_on_boundary=TRUE,filename="",...) 

Arguments

x	SpatRaster with flow-direcion. See flowDir
pits_on_boundary	logical if TRUE (default) pits are considered also on the boundary. If FALSE pits are considered only within the terrain domain.
filename	character. Output filename
...	additional arguments for writing files as in writeRaster

Value

SpatRaster with positive integers (1, 2, 3, ...) to identify pits and zero elsewhere.

Author(s)

Emanuele Cordano

See Also

terrain, watershed, flowAccumulation, NIDP

Examples

## example elevation data

elev <- array(NA,c(9,9))
dx <- 1
dy <- 1 
for (r in 1:nrow(elev)) {
	x <- (r-5)*dx
	for (c in 1:ncol(elev)) {
		y <- (c-5)*dy
		elev[r,c] <- 10+5*(x^2+y^2)
    }
} 
  
elev <- cbind(elev,elev,elev,elev) 
elev <- rbind(elev,elev,elev,elev) 
elev <- rast(elev)

## Flow Directions

flowdir<- terrain(elev,v="flowdir")
t(array(flowdir[],rev(dim(flowdir)[1:2])))

## detect pits
pits <- pitfinder(flowdir)

## Application with example DEM

elev <- rast(system.file('ex/elev.tif',package="terra"))
flowdir <- terrain(elev, "flowdir")

pits <- pitfinder(flowdir)
pits2 <- pitfinder(flowdir, pits_on_boundary=FALSE)
plot((pits>0)==(pits2>0))

terra documentation built on Aug. 22, 2026, 5:07 p.m.