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\name{weighted.mean}
\alias{weighted.mean}
\alias{weighted.mean,RasterStackBrick,vector-method}
\alias{weighted.mean,RasterStackBrick,RasterStackBrick-method}
\title{Weighted mean of rasters}
\description{
Computes the weighted mean for each cell of a number or raster layers. The weights can be spatially variable or not.
}
\usage{
\S4method{weighted.mean}{RasterStackBrick,vector}(x, w, na.rm=FALSE, filename='', ...)
\S4method{weighted.mean}{RasterStackBrick,RasterStackBrick}(x, w, na.rm=FALSE,filename='', ...)
}
\arguments{
\item{x}{RasterStack or RasterBrick}
\item{w}{A vector of weights (one number for each layer), or for spatially variable weights, a RasterStack or RasterBrick with weights (should have the same extent, resolution and number of layers as x)}
\item{na.rm}{Logical. Should missing values be removed?}
\item{filename}{Character. Output filename (optional)}
\item{...}{Additional arguments as for \code{\link{writeRaster}}}
}
\value{
RasterLayer
}
\seealso{
\code{\link{Summary-methods}}, \code{\link[stats]{weighted.mean}}
}
\examples{
b <- brick(system.file("external/rlogo.grd", package="raster"))
# give least weight to first layer, most to last layer
wm1 <- weighted.mean(b, w=1:3)
# spatially varying weights
# weigh by column number
w1 <- init(b, v='col')
# weigh by row number
w2 <- init(b, v='row')
w <- stack(w1, w2, w2)
wm2 <- weighted.mean(b, w=w)
}
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