sapp function

Apply a terra function that takes only a single layer and returns a SpatRaster to all layers of a SpatRaster

Apply to all layers of a SpatRaster a function that only takes a single layer SpatRaster and returns a SpatRaster (these are rare). In most cases you can also use lapply or sapply for this.

Or apply the same method to each sub-dataset (SpatRaster) in a SpatRasterDataset methods

## S4 method for signature 'SpatRaster'
sapp(x, fun, ..., filename="", overwrite=FALSE, wopt=list())

## S4 method for signature 'SpatRasterDataset'
sapp(x, fun, ..., filename="", overwrite=FALSE, wopt=list())

Arguments

• x: SpatRaster or SpatRasterDataset
• fun: if x is a SpatRaster: a function that takes a SpatRaster argument and can be applied to each layer of x (e.g. terrain. if x is a SpatRasterDataset: a function that is applied to all layers of the SpatRasters in x (e.g. mean
• ...: additional arguments to be passed to fun
• filename: character. Output filename
• overwrite: logical. If TRUE, filename is overwritten
• wopt: list with named options for writing files as in writeRaster

Returns

SpatRaster

See Also

lapp, app, tapp, lapply

Examples

s <- rast(system.file("ex/logo.tif", package="terra")) + 1  

#SpatRasterDataset
sd <- sds(s*2, s/2)
y <- sapp(sd, mean)
z <- sapp(sd, function(i) 2 * mean(i))