terra (version 1.6-17)

merge: Merge multiple SpatRaster objects or SpatExtent objects, or merge a SpatVector with a data.frame

Description

Merge multiple SpatRasters to create a new SpatRaster object with a larger spatial extent. The SpatRasters must have the same origin and spatial resolution. In areas where the SpatRasters overlap, the values of the SpatRaster that is first in the sequence of arguments (or in the SpatRasterCollection) will be retained. See classify to merge a SpatRaster and a data.frame. You can also merge SpatExtent objects.

There is a also a method for merging SpatVector with a data.frame; that is, to join the data.frame to the attribute table of the SpatVector.

Usage

# S4 method for SpatRaster,SpatRaster
merge(x, y, ..., filename="", overwrite=FALSE, wopt=list())
# S4 method for SpatRasterCollection,missing
merge(x, filename="", ...)
# S4 method for SpatExtent,SpatExtent
merge(x, y, ...)
# S4 method for SpatVector,data.frame
merge(x, y, ...)

Value

SpatRaster or SpatExtent

Arguments

x

SpatRaster or SpatExtent

y

object of same class as x

...

if x is a SpatRaster: additional objects of the same class as x. If x is a SpatRasterCollection: options for writing files as in writeRaster. If x is a SpatVector, the same arguments as in merge

filename

character. Output filename

overwrite

logical. If TRUE, filename is overwritten

wopt

list with named options for writing files as in writeRaster

See Also

Combining tiles with vrt may be more efficient. See mosaic for averaging overlapping regions.

Examples

x <- rast(xmin=-110, xmax=-80, ymin=40, ymax=70, ncols=30, nrows=30)
y <- rast(xmin=-85, xmax=-55, ymax=60, ymin=30, ncols=30, nrows=30)
z <- rast(xmin=-60, xmax=-30, ymax=50, ymin=20, ncols=30, nrows=30)
values(x) <- 1:ncell(x)
values(y) <- 1:ncell(y)
values(z) <- 1:ncell(z)

m1 <- merge(x, y, z)
m2 <- merge(z, y, x)
m3 <- merge(y, x, z)

# if you have many SpatRasters make a SpatRasterCollection from a list
rlist <- list(x, y, z)
rsrc <- sprc(rlist)

m <- merge(rsrc)


## SpatVector with data.frame
f <- system.file("ex/lux.shp", package="terra")
p <- vect(f)
dfr <- data.frame(District=p$NAME_1, Canton=p$NAME_2, Value=round(runif(length(p), 100, 1000)))
dfr <- dfr[1:5, ]
pm <- merge(p, dfr, all.x=TRUE, by.x=c('NAME_1', 'NAME_2'), by.y=c('District', 'Canton'))
pm
values(pm)