intersect: Intersection

In terra: Spatial Data Analysis

Intersection

Description

You can intersect SpatVectors with each other or with a SpatExtent. Intersecting points with points uses the extent of y to get the intersection. Intersecting of points and lines is not supported because of numerical inaccuracies with that. You can use buffer, to create polygons from lines and use these with intersect.

You can also intersect two SpatExtents.

When intersecting two SpatRasters these need to be aligned (have the same origin and spatial resolution). The values of the returned SpatRaster are TRUE where both input rasters have values, FALSE where one has values, and NA in all other cells.

When intersecting a SpatExtent and a SpatRaster, the SpatExtent is first aligned to the raster cell boundaries.

See crop for the intersection of a SpatRaster with a SpatExtent (or the extent of a SpatRaster or SpatVector) if you want a SpatRaster (not a SpatExtent) as output.

See is.related(x, y, "intersects") to find out which geometries of a SpatVector intersect. You can spatially subset a SpatVector with another one with x[y].

Usage

## S4 method for signature 'SpatVector,SpatVector'
intersect(x, y)

## S4 method for signature 'SpatVector,SpatExtent'
intersect(x, y)

## S4 method for signature 'SpatExtent,SpatVector'
intersect(x, y)

## S4 method for signature 'SpatExtent,SpatExtent'
intersect(x, y)

## S4 method for signature 'SpatRaster,SpatRaster'
intersect(x, y)

## S4 method for signature 'SpatRaster,SpatExtent'
intersect(x, y)

## S4 method for signature 'SpatExtent,SpatRaster'
intersect(x, y)

Arguments

x	SpatVector, SpatExtent, or SpatRaster
y	SpatVector, SpatExtent, or SpatRaster

Value

Same as x

See Also

union, crop, relate, [

Examples

e1 <- ext(-10, 10, -20, 20)
e2 <- ext(0, 20, -40, 5)
intersect(e1, e2)

f <- system.file("ex/lux.shp", package="terra")
v <- vect(f)
e <- ext(5.6, 6, 49.55, 49.7)
x <- intersect(v, e)

p <- vect(c("POLYGON ((5.8 49.8, 6 49.9, 6.15 49.8, 6 49.6, 5.8 49.8))", 
"POLYGON ((6.3 49.9, 6.2 49.7, 6.3 49.6, 6.5 49.8, 6.3 49.9))"), crs=crs(v))
values(p) <- data.frame(pid=1:2, area=expanse(p))

y <- intersect(v, p)

r <- s <- rast(ncol=5, nrow=5, xmin=1, xmax=5, ymin=1, ymax=5)
r[5:20] <- 5:20
s[11:20] <- 11:20
rs <- intersect(r, s)

u <- shift(r, .8)
us <- intersect(u, s)

terra documentation built on April 12, 2025, 1:43 a.m.