How to compute an average year on time series ?
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 spacetime does not provide this, but zoo does; see the last example in ?aggregate.zoo. I'd try something along these lines: pix = obj at sp obj = as.zoo(obj) obj = aggregate(obj, format(time(obj), "%m"), mean,na.rm=TRUE) sp = SpatialPixelsDataFrame(pix, data.frame(t(obj))) you may need to give the data.frame() meaningful names before passing them into the SpatialPixelsDataFrame.
On 07/25/2013 05:09 PM, Nicolas Bories wrote:
Edzer, Thanks for helping me and sorry for my late answer. I think didn't express myself very well. Actually, I would like, for each pixel, to have a mean year (23 values). So each value will be an average of the EVI at the same date for the 10 years. Regards, Nicolas. On 27/06/2013 12:34, Edzer Pebesma wrote:
Given your data are in obj, did you try mean.yrs = aggregate(obj, "year", mean) ? On 06/27/2013 10:56 AM, Nicolas Bories wrote:
Dear all, I'm working on EVI-MODIS time series with the R package spacetime. I have 10 years of data. I want to compute an average year for each pixel. How can I do this ? The goal is to compare for each pixel and for specific years the EVI-MODIS variations and average year variations. I saw the method aggregate(x, by, FUN = mean, ..., simplify = TRUE) but I didn't manage to get an average year. Thanks in advance for any suggestions ! Nicolas. [[alternative HTML version deleted]]
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