[R-sig-Geo] gridded time series analysis

[Robert J. Hijmans]

Martin,

I think the problem is whith the lm function that returns an error
rather than NA:

> a <- rep(NA,10)
> lm(a~a)
Error in lm.fit(x, y, offset = offset, singular.ok = singular.ok, ...) :
  0 (non-NA) cases

#rather than something like this:
> fun=function(x) { lm(x[1]~x[2])$coefficients[2] }
> fun(c(NA,NA))
Error in lm.fit(x, y, offset = offset, singular.ok = singular.ok, ...) :
  0 (non-NA) cases

#you could catch this in your function and do something like:

> fun=function(x) { if (is.na(x[1])){ NA } else { lm(x[1]~x[2])$coefficients[2] }}
> fun(c(NA,NA))
[1] NA


and then:

calc(s, fun=fun)

lm and relatives have an na.action argument but I do not think that
can come to the rescue here.

Roberrt

On Sun, Nov 28, 2010 at 4:33 AM, Martin <martin_brandt at gmx.net> wrote:
>
> thanks Robert, this works fine.
> but could it be that the functions have a problem with NA-values?
> your Regression functions return this error:
>
>
>> x3 <- calc(tt, fun)
> error in lm.fit(x, y, offset = offset, singular.ok = singular.ok, ...) :
>  0 (non-NA) cases
>
> when i use rasters with NA values...it works without problems with rasters
> without NAs..
>
> cheers,
> Martin
>
>
>
>
> --
> View this message in context: http://r-sig-geo.2731867.n2.nabble.com/gridded-time-series-analysis-tp5775651p5781554.html
> Sent from the R-sig-geo mailing list archive at Nabble.com.
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>