Hi John, One way is to create an index variable that will divide your data into the appropriate intervals. There are a number of ways to do this. Say you want the "two month" version of bimonthly and you have a date variable ("raindate") for each observation like "1982-01-01".
date_order<-paste(rep(month.abb,30),rep(1982:2011,each=12),sep="") month_index<-factor(format(as.Date(raindate,"%Y-%m-%d"),"%b%Y"),levels=date_order) You can then subset the raster matrices by "month_index" and average them for each group Jim On Mon, Apr 6, 2015 at 3:08 AM, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > Please stop posting using HTML (as the Posting Guide warns you), and > follow John Kane's advice. Your reply below is not helping us understand as > well as you seem to think it should. > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live > Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > --------------------------------------------------------------------------- > Sent from my phone. Please excuse my brevity. > > On April 5, 2015 9:52:18 AM PDT, John Wasige <johnwas...@gmail.com> wrote: > >Thanks Bert, > > > >The structure of the data is a raster stack with nraw=867, Ncol=995 > > > >Rgds John > > > > > >On Sun, Apr 5, 2015 at 6:39 PM, Bert Gunter <gunter.ber...@gene.com> > >wrote: > > > >> See ?tapply > >> > >> However, as John said, without knowing the structure of your data, it > >> is impossible to provide a guaranteed recipe. For example, does the > >> data structure contain date information? -- it would be difficult > >(but > >> not impossible depending on data structure) to aggregate by calendar > >> (bi-monthly, depending on your meaning of "bi") without knowing the > >> months. Aggregating by every n days would be easy, but that's > >probably > >> not what you want. > >> > >> Cheers, > >> Bert > >> > >> Bert Gunter > >> Genentech Nonclinical Biostatistics > >> (650) 467-7374 > >> > >> "Data is not information. Information is not knowledge. And knowledge > >> is certainly not wisdom." > >> Clifford Stoll > >> > >> > >> > >> > >> On Sun, Apr 5, 2015 at 9:13 AM, John Kane <jrkrid...@inbox.com> > >wrote: > >> > Someone might if they had any idea of what the data actually looked > >like > >> and what you are trying to do. The 'bimonthly' for example, is > >ambiguous in > >> English; do you mean every two months or twice a month? > >> > > >> > Have a look at > >https://github.com/hadley/devtools/wiki/Reproducibility > >> and > >> > > > http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example > >> with special attention to dput() as a method of supplying sample data > >to > >> the help list. > >> > > >> > John Kane > >> > Kingston ON Canada > >> > > >> > > >> >> -----Original Message----- > >> >> From: johnwas...@gmail.com > >> >> Sent: Sun, 5 Apr 2015 11:34:30 +0200 > >> >> To: r-help@r-project.org > >> >> Subject: [R] Aggregating daily rainfall raster data to bimontly > >data > >> >> > >> >> Dear community, > >> >> > >> >> I have daily rainfall raster data for 30 years (1982_2011). I > >would like > >> >> to > >> >> aggregate daily to bimonthly raster data. Could somebody kindly > >help on > >> >> how > >> >> to go about it! > >> >> > >> >> Thanks for your help > >> >> > >> >> -- > >> >> John > >> >> > >> >> [[alternative HTML version deleted]] > >> >> > >> >> ______________________________________________ > >> >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > >> >> https://stat.ethz.ch/mailman/listinfo/r-help > >> >> PLEASE do read the posting guide > >> >> http://www.R-project.org/posting-guide.html > >> >> and provide commented, minimal, self-contained, reproducible code. > >> > > >> > ____________________________________________________________ > >> > FREE ONLINE PHOTOSHARING - Share your photos online with your > >friends > >> and family! > >> > Visit http://www.inbox.com/photosharing to find out more! > >> > > >> > ______________________________________________ > >> > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > >> > https://stat.ethz.ch/mailman/listinfo/r-help > >> > PLEASE do read the posting guide > >> http://www.R-project.org/posting-guide.html > >> > and provide commented, minimal, self-contained, reproducible code. > >> > > > > [[alternative HTML version deleted]] > > > >______________________________________________ > >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > >https://stat.ethz.ch/mailman/listinfo/r-help > >PLEASE do read the posting guide > >http://www.R-project.org/posting-guide.html > >and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.