search for: stand_height

Sorry for the confusion, here is the edited question. The data= Stand_Height (attached) is recorded from 12/1/2009 to 12/31/2015 (25 observations) and the other dataset (leafbiom) is recorded from 10/7/2009 to 12/29/2016 (daily observations). I want to use the 25 observations of stand height to predict the daily stand height from 10/7/2009 to 12/29/2016. The daily stand he...

Once again, you are over-writing your variable. This time, you are overwriting the entirety of Stand_Height with the timeseries of height. Perhaps you should spend some time with one of the good introductory R resources out there, and think a bit more about your procedure. Sarah On Fri, Jun 30, 2017 at 11:23 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > Sorry for the confusion, here is...

...ght observations over 7 years period and daily leafbiomass data during this period. I want to use the 25 plant height observations as inputs and predict the daily stand height during the 7 years. SH=matrix(data=NA , nrow = 2641, ncol = 1) for (i in 1:2641) { SH<- predict(lm(height~Date, data=Stand_Height)); dl=leafbiom$Date[i-1]; de=leafbiom$Date[i]; SH[i]=sum(SH[leafbiom$Date==de&leafbiom$Date==dl]) } SH The SH output is the prediction of Stand height in 25 observations only and provides NA for the remaining 2616 iterations. Thanks for your help. Ahmed Attia, Ph.D. Agronomist &amp...

...s never used for anything. I would have thought that you would use leaf biomass as the predictor variable, not Date. - I'm not sure why you want the cumulative sum of stand height; that doesn't make sense to me. I'm guessing you want: height.model <- lm(height ~ leafbiomass, data = Stand_Height) pred.height <- predict(height.model, leafbiom) # not sure about the reasoning behind this SH <- cumsum(pred.height) You don't need a loop. Overwriting SH is the biggest R problem; the rest of my questions have to do with what your objective actually is, like what you are modeling and w...