How to calculate decadal average and percent change in raster stacks?
Hi Thiago,
This should work for aggregating to decades.
library(raster)
library(lubridate)
# Create the date sequence
idx <- seq(as.Date("2010/1/1"), as.Date("2099/12/31"), by = "year")
# Create raster stack and apply the date
r <- raster(ncol=360, nrow=180)
s <- stack(lapply(1:length(idx), function(x) setValues(r, runif(ncell(r)))))
s <- setZ(s, idx)
# Aggregate to decades
zApply(s, by = function(x) year(x) %/% 10 * 10, fun = mean)
By calculate percent change for each decade, do you mean between decades
or within?
Cheers,
Lo?c
On 12/01/2015 09:14 AM, Thiago V. dos Santos wrote:
Dear all,
I am working with yearly climate projections of rainfall that cover the period from 2010 to 2099:
library(raster)
# Create the date sequence
idx <- seq(as.Date("2010/1/1"), as.Date("2099/12/31"), by = "year")
# Create raster stack and apply the date
r <- raster(ncol=360, nrow=180)
s <- stack(lapply(1:length(idx), function(x) setValues(r, runif(ncell(r)))))
s <- setZ(s, idx)
s
Given this raster stack, how can I calculate the average values per decade and percent change for each decade?
I define decades here as 2010-2019, 2020-2029, 2030-2039 and so on until 2090-2099.
I guess the real issue here is how to "split" a raster stack in decades. Any ideas?
Thanks,
-- Thiago V. dos Santos
PhD student
Land and Atmospheric Science
University of Minnesota
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