zApply function

z (time) apply

Experimental function to apply a function over a (time) series of layers of a Raster object

zApply(x, by, fun=mean, name='', ...)

Arguments

• x: Raster* object
• by: aggregation indices or function
• fun: function to compute aggregated values
• name: character label of the new time series
• ...: additional arguments

Returns

Raster* object

Author(s)

Oscar Perpinan Lamigueiro & Robert J. Hijmans

Examples

# 12 values of irradiation, 1 for each month
G0dm=c(2.766,3.491,4.494,5.912,6.989,7.742,7.919,7.027,5.369,3.562,2.814,2.179)*1000;
# RasterBrick with 12 layers based on G0dm + noise
r <- raster(nc=10, nr=10)
s <- brick(lapply(1:12, function(x) setValues(r, G0dm[x]+100*rnorm(ncell(r)) )))

# time
tm <- seq(as.Date('2010-01-15'), as.Date('2010-12-15'), 'month')
s <- setZ(s, tm, 'months')

# library(zoo)
# x <- zApply(s, by=as.yearqtr, fun=mean, name='quarters')