raster: cellStats – R documentation

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cellStats

Statistics across cells

Description

Compute statistics for the cells of each layer of a Raster* object. In the raster package, functions such as max, min, and mean, when used with Raster* objects as argument, return a new Raster* object (with a value computed for each cell). In contrast, cellStats returns a single value, computed from the all the values of a layer. Also see layerStats

Usage

## S4 method for signature 'RasterLayer'
cellStats(x, stat='mean', na.rm=TRUE, asSample=TRUE, ...)

## S4 method for signature 'RasterStackBrick'
cellStats(x, stat='mean', na.rm=TRUE, asSample=TRUE, ...)

Arguments

`x`	Raster* object
`stat`	The function to be applied. See Details
`na.rm`	Logical. Should `NA` values be removed?
`asSample`	Logical. Only relevant for `stat=sd` in which case, if `TRUE`, the standard deviation for a sample (denominator is `n-1`) is computed, rather than for the population (denominator is `n`)
`...`	Additional arguments

Details

cellStats will fail (gracefully) for very large Raster* objects except for a number of known functions: sum, mean, min, max, sd, 'skew' and 'rms'. 'skew' (skewness) and 'rms' (Root Mean Square) must be supplied as a character value (with quotes), the other known functions may be supplied with or without quotes. For other functions you could perhaps use a sample of the RasterLayer that can be held in memory (see sampleRegular )

Value

Numeric

Examples

r <- raster(nrow=18, ncol=36)
values(r) <- runif(ncell(r)) * 10
# works for large files
cellStats(r, 'mean')
# same, but does not work for very large files
cellStats(r, mean)
# multi-layer object
cellStats(brick(r,r), mean)

raster

Geographic Data Analysis and Modeling

v3.4-10

GPL (>= 3)

Authors

Robert J. Hijmans [cre, aut] (<https://orcid.org/0000-0001-5872-2872>), Jacob van Etten [ctb], Michael Sumner [ctb], Joe Cheng [ctb], Dan Baston [ctb], Andrew Bevan [ctb], Roger Bivand [ctb], Lorenzo Busetto [ctb], Mort Canty [ctb], Ben Fasoli [ctb], David Forrest [ctb], Aniruddha Ghosh [ctb], Duncan Golicher [ctb], Josh Gray [ctb], Jonathan A. Greenberg [ctb], Paul Hiemstra [ctb], Kassel Hingee [ctb], Institute for Mathematics Applied Geosciences [cph], Charles Karney [ctb], Matteo Mattiuzzi [ctb], Steven Mosher [ctb], Babak Naimi [ctb], Jakub Nowosad [ctb], Edzer Pebesma [ctb], Oscar Perpinan Lamigueiro [ctb], Etienne B. Racine [ctb], Barry Rowlingson [ctb], Ashton Shortridge [ctb], Bill Venables [ctb], Rafael Wueest [ctb]

Initial release

2021-05-02