Subsetting Raster Time Series
You could use the calc() environment and define your own function where
you create a ts() object and then subset the ts() using window() to your
time period.
f_subset <- function(x) {
x <- ts(x, start = c(1901, 1), frequency = 12) # fill in the right values
sx <- window(x, start = c(?,?), end = c(?,?)) ## fill in the right values
return(sx)
}
result <- calc(temp, fun = f_subset)
Jan
www.wageningenur.nl/changemonitor
On 26/08/14 11:55, "Srinivas V" <srinivasv at feralindia.org> wrote:
Hi,
I would like to subset the CRU dataset to a particular time period
(1980-2013) is there an option to do this within package raster? I can
manually specifiy the layers to drop, but I would like to drop them
based on a time period. I'm doing this to ensure two datasets are of the
same time period.
I would appreciate any advice on dealing with this issue. Thanks!
library(raster)
library(rgdal)
library(ncdf)
library(zoo)
temp<-brick("/media/data/data_cru/tmp/cru_ts3.22.1901.2013.tmp.dat.nc")
temp
temp at z
output
+++++
temp
class : RasterBrick dimensions : 360, 720, 259200, 1356 (nrow, ncol, ncell, nlayers) resolution : 0.5, 0.5 (x, y) extent : -180, 180, -90, 90 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0 data source : /media/data/data_cru/tmp/cru_ts3.22.1901.2013.tmp.dat.nc names : X1901.01.16, X1901.02.15, X1901.03.16, X1901.04.16, X1901.05.16, X1901.06.16, X1901.07.16, X1901.08.16, X1901.09.16, X1901.10.16, X1901.11.16, X1901.12.16, X1902.01.16, X1902.02.15, X1902.03.16, ... Date : 1901-01-16, 2013-12-16 (min, max) varname : tmp
temp at z
$Date [1] "1901-01-16" "1901-02-15" "1901-03-16" "1901-04-16" "1901-05-16" "1901-06-16" "1901-07-16" "1901-08-16" "1901-09-16" "1901-10-16" [1351] "2013-07-16" "2013-08-16" "2013-09-16" "2013-10-16" "2013-11-16" "2013-12-16" -- Srinivas Vaidyanathan Senior Research Fellow Foundation for Ecological Research, Advocacy & Learning Web: www.feralindia.org [[alternative HTML version deleted]]
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