raster (version 2.5-8)

merge: Merge Raster* objects

Description

Merge Raster* objects to form a new Raster object with a larger spatial extent. If objects overlap, the values get priority in the same order as the arguments, but NA values are ignored (except when overlap=FALSE). See subs to merge a Raster* object and a data.frame.

Usage

# S4 method for Raster,Raster
merge(x, y, ..., tolerance=0.05, filename="", overlap=TRUE, ext=NULL)
# S4 method for RasterStackBrick,missing
merge(x, ..., tolerance=0.05, filename="", ext=NULL)
# S4 method for Extent,ANY
merge(x, y, ...)

Arguments

x

Raster* or Extent object

y

Raster* if x is a Raster* object (or missing). If x is an Extent, y can be an Extent or object from which an Extent can be extracted

...

additional Raster or Extent objects (and/or arguments for writing files as in writeRaster)

tolerance

numeric. permissible difference in origin (relative to the cell resolution). See all.equal

filename

character. Output filename (optional)

overlap

logical. If FALSE values of overlapping objects are based on the first layer, even if they are NA

ext

Extent object (optional) to limit the output to that extent

Value

RasterLayer or RasterBrick

Details

The Raster objects must have the same origin and resolution. In areas where the Raster objects overlap, the values of the Raster object that is first in the sequence of arguments will be retained. If you would rather use the average of cell values, or do another computation, you can use mosaic instead of merge.

Examples

# NOT RUN {
r1 <- raster(xmx=-150, ymn=60, ncols=30, nrows=30)
r1[] <- 1:ncell(r1)
r2 <- raster(xmn=-100, xmx=-50, ymx=50, ymn=30)
res(r2) <- c(xres(r1), yres(r1))
r2[] <- 1:ncell(r2)
rm <- merge(r1, r2)

# if you have many RasterLayer objects in a list
# you can use do.call:
x <- list(r1, r2)
# add arguments such as filename
# x$filename <- 'test.tif'
m <- do.call(merge, x)
# }