extend: Extend

In terra: Spatial Data Analysis

Extend

Description

Enlarge the spatial extent of a SpatRaster. See crop if you (also) want to remove rows or columns.

Note that you can only enlarge SpatRasters with entire rows and columns. Therefore, the extent of the output SpatRaster may not be exactly the same as the requested. Depending on argument snap it may be a bit smaller or larger.

You can also enlarge a SpatExtent with this method, or with an algebraic notation (see examples)

Usage

## S4 method for signature 'SpatRaster'
extend(x, y, snap="near", fill=NA, filename="", overwrite=FALSE, ...) 

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

Arguments

x	SpatRaster or SpatExtent
y	If x is a SpatRaster, y should be a SpatExtent, or an object from which it can be extracted (such as SpatRaster and SpatVector objects). Alternatively, you can provide one, two or four non-negative integers indicating the number of rows and columns that need to be added at each side (a single positive integer when the number of rows and columns to be added is equal; or 2 number (columns, rows), or four (left column, right column, bottom row, top row). If x is a SpatExtent, y should likewise be a numeric vector of 1, 2, or 4 elements
snap	character. One of "near", "in", or "out". Used to align y to the geometry of x
fill	numeric. The value used to for the new raster cells
filename	character. Output filename
overwrite	logical. If TRUE, filename is overwritten
...	additional arguments for writing files as in writeRaster

Value

SpatRaster or SpatExtent

See Also

crop, merge, ext, resample, elongate

Examples

r <- rast(xmin=-150, xmax=-120, ymin=30, ymax=60, ncols=36, nrows=18)
values(r) <- 1:ncell(r)
e <- ext(-180, -100, 40, 70)
re <- extend(r, e)

# extend with a number of rows and columns (at each side)
re2 <- extend(r, c(2,10))

# SpatExtent
e <- ext(r)
e
extend(e, 10)
extend(e, c(10, -10, 0, 20))


# add 10 columns / rows on all sides
e + 10
# double extent
e * 2
# increase extent by 25%
e * 1.25

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