crop: Cut out a geographic subset

cropR Documentation

Cut out a geographic subset

Description

Cut out a part of a SpatRaster with a SpatExtent, or another object from which an extent can be obtained.

You can only crop rectangular areas, but see mask for setting cell values within SpatRaster to NA. Also note that the SpatRaster returned may not have the exactly the same extent as the SpatExtent supplied because you can only select entire cells (rows and columns), and you cannot add new areas. See methods like resample and disagg to force SpatRasters to align and extend to add rows and/or columns.

You can crop a SpatVector with another SpatVector. If these are not polygons, the minimum convex hull is used). Unlike with intersect the geometries and attributes of y are not transferred to the output. You can also crop a SpatVector with a rectangle (SpatRaster, SpatExtent).

Usage

## S4 method for signature 'SpatRaster'
crop(x, y, snap="near", mask=FALSE, touches=TRUE, extend=FALSE, filename="", ...)

## S4 method for signature 'SpatRasterDataset'
crop(x, y, snap="near", extend=FALSE)

## S4 method for signature 'SpatRasterCollection'
crop(x, y, snap="near", extend=FALSE)

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

## S4 method for signature 'SpatGraticule'
crop(x, y)

Arguments

x

SpatRaster or SpatVector

y

SpatRaster, SpatVector, SpatExtent or other object that has a SpatExtent (ext returns a SpatExtent)

snap

character. One of "near", "in", or "out". Used to align y to the geometry of x

mask

logical. Should y be used to mask? Only used if y is a SpatVector or SpatRaster

touches

logical. If TRUE and mask=TRUE, all cells touched by lines or polygons will be masked, not just those on the line render path, or whose center point is within the polygon

extend

logical. Should rows and/or columns be added if y is beyond the extent of x? Also see extend

filename

character. Output filename

...

additional arguments for writing files as in writeRaster

Value

SpatRaster

See Also

intersect, extend

Examples

r <- rast(xmin=0, xmax=10, ymin=0, ymax=10, nrows=25, ncols=25)
values(r) <- 1:ncell(r)
e <- ext(-5, 5, -5, 5)
rc <- crop(r, e)

# crop and mask
f <- system.file("ex/elev.tif", package="terra")
r <- rast(f)
f <- system.file("ex/lux.shp", package="terra")
v <- vect(f)
cm <- crop(r, v[9:12,], mask=TRUE)
plot(cm)
lines(v)

# crop vector
f <- system.file("ex/lux.shp", package="terra")
v <- vect(f)
e <- ext(6.15, 6.3, 49.7, 49.8)
x <- crop(v, e)
plot(x, "NAME_1")

terra documentation built on Dec. 2, 2022, 5:13 p.m.