[R] raster time series statistics

[Alexander.Herr at csiro.au]

Thanks Jim

Still getting the same error for apply.montly
Updated code:

require(raster)
require(rts)
require(stringr)
r <- raster(ncol=100, nrow=100)
values(r) <- runif(ncell(r))
stack(r)->s
r->rs
for(i in 1:23){
 rs[]<-r[]*i
  addLayer(s,rs)->s
 print(nlayers(s))
}
dt<-list(ID=seq(1:24),month=rep(formatC(1:12,flag=0,width=2),2),
 year=sort(rep(2016:2017,12)))
 timelst<-paste0(unlist(dt['year']),'-',unlist(dt['month']),"-01")
strptime(timelst,format="%Y-%m-%d")->t1

rts(s,time=as.yearmon(t1))->rsts
subset(rsts,'2017')->r2017
class(r2017 at time)
class(rsts at time)

apply.monthly(rsts,mean)



-----Original Message-----
From: Jim Lemon [mailto:drjimlemon at gmail.com] 
Sent: Tuesday, 6 March 2018 11:14 AM
To: Herr, Alexander (L&W, Black Mountain) <Alexander.Herr at csiro.au>
Cc: r-help mailing list <r-help at r-project.org>
Subject: Re: [R] raster time series statistics

Hi Herry,
This is probably due to a call to strptime (or similar). No, it doesn't accept %Y-%m as a valid format. Maybe add a constant day to all the dates as that will work:

dt<-list(ID=seq(1:24),month=rep(formatC(1:12,flag=0,width=2),2),
 year=sort(rep(2016:2017,12)))
timelst<-paste(unlist(dt['year']),unlist(dt['month']),"01",sep="-")
strptime(timelst,format="%Y-%m-%d")

Jim



On Tue, Mar 6, 2018 at 10:28 AM,  <Alexander.Herr at csiro.au> wrote:
> Hi List,
>
> The following code returns an "Error in as.POSIXlt.character(x, tz, ...) :   character string is not in a standard unambiguous format"
>
> require(raster)
> require(rts)
> require(stringi)
> r <- raster(ncol=100, nrow=100)
> values(r) <- runif(ncell(r))
> list(ID=seq(1:24),month=rep(str_pad(1:12, pad = 0,width = 2 , 
> "left"),2),year=sort(rep(2016:2017,12)))->dt
> stack(r)->s
> r->rs
> for(i in 1:23){
> rs[]<-r[]*i
>   addLayer(s,rs)->s
> print(nlayers(s))
> }
> timelst<-paste0(unlist(dt['year']),'-',unlist(dt['month']))
> rts(s,time=as.yearmon(timelst))->rsts
> str(rsts at time)
> apply.monthly(rsts,mean)
>
> I was expecting that the statistics accept the yearmonth format of the timeslot, as it allows subsetting.
> Any suggestions?
> Thanks
> Herry
>
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