merge function

Merge Raster* objects

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. methods

## S4 method for signature 'Raster,Raster'
merge(x, y, ..., tolerance=0.05, filename="", overlap=TRUE, ext=NULL)

## S4 method for signature 'RasterStackBrick,missing'
merge(x, ..., tolerance=0.05, filename="", ext=NULL)

## S4 method for signature '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

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.

Returns

RasterLayer or RasterBrick

Examples

r1 <- raster(xmx=-150, ymn=60, ncols=30, nrows=30)
values(r1) <- 1:ncell(r1)
r2 <- raster(xmn=-100, xmx=-50, ymx=50, ymn=30)
res(r2) <- c(xres(r1), yres(r1))
values(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)