Re: [R] Interpolation in time

2005-10-06 Thread Gabor Grothendieck 
na.approx(zoo(ta[,-seq(2)], tt))

where tt is as before.


On 10/6/05, Anette Nørgaard <[EMAIL PROTECTED]> wrote:
> This is exactly what I requested, thank you!! However I do actually have
> several columns in my data sheet where I need to do the same thing, then
> how do I come about that?
>
> e.g.
>
> yr<-c(rep(2000,14))
> doy<-c(16:29)
> dat1<-c(3.2,NA,NA,NA,NA,NA,NA,5.1,NA,NA,NA,NA,NA,4.6)
> dat2<-c(2.2,NA,NA,NA,NA,NA,NA,6.1,NA,NA,NA,NA,NA,4.2)
> dat3<-c(3.4,NA,NA,NA,NA,NA,NA,4.1,NA,NA,NA,NA,NA,4.7)
> ta<-cbind(yr,doy,dat1,dat2,dat3)
>
>
>
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>
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Re: [R] Interpolation in time

2005-10-06 Thread Gabor Grothendieck 
Is doy intended to represent the number of days since the beginning
of the year?  In that case convert the first two columns to class Date
and interpolate using approx.  See ?approx for variations:

tt <- as.Date(paste(yr, 1, 1, sep = "-")) + doy - 1
ta[,"dat"] <- approx(tt, dat, tt)$y

Even better would be to create an irregular time series object.

library(zoo)
tt <- as.Date(paste(yr, 1, 1, sep = "-")) + doy - 1
ta.z <- na.approx(zoo(dat, tt))

Now ta.z is a zoo object representing your time series. coredata(ta.z)
is the data and time(ta.z) are the dates.  See:

library(zoo)
vignette("zoo")

for more info.




On 10/6/05, Anette Nørgaard <[EMAIL PROTECTED]> wrote:
> Can anybody help me write a code on the following data example, which
> fills out all NA values by using a linear interpolation with the two
> closest values?
>
> Doy is day of year (%j).
>
> Code example:
> yr<-c(rep(2000,14))
> doy<-c(16:29)
> dat<-c(3.2,NA,NA,NA,NA,NA,NA,5.1,NA,NA,NA,NA,NA,4.6)
> ta<-cbind(yr,doy,dat)
>
> ta
>  yr doy dat
>  [1,] 2000  16 3.2
>  [2,] 2000  17  NA
>  [3,] 2000  18  NA
>  [4,] 2000  19  NA
>  [5,] 2000  20  NA
>  [6,] 2000  21  NA
>  [7,] 2000  22  NA
>  [8,] 2000  23 5.1
>  [9,] 2000  24  NA
> [10,] 2000  25  NA
> [11,] 2000  26  NA
> [12,] 2000  27  NA
> [13,] 2000  28  NA
> [14,] 2000  29 4.6
>
> Anette Norgaard
>
>[[alternative HTML version deleted]]
>
> __
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>

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Re: [R] Interpolation in time

2005-10-06 Thread Achim Zeileis 
On Thu, 6 Oct 2005 16:10:15 +0200 Anette Nørgaard wrote:

> This is exactly what I requested, thank you!! However I do actually
> have several columns in my data sheet where I need to do the same
> thing, then how do I come about that?

Look at na.approx() in package zoo.
Best,
Z
  
> e.g.
>  
> yr<-c(rep(2000,14))
> doy<-c(16:29)
> dat1<-c(3.2,NA,NA,NA,NA,NA,NA,5.1,NA,NA,NA,NA,NA,4.6)
> dat2<-c(2.2,NA,NA,NA,NA,NA,NA,6.1,NA,NA,NA,NA,NA,4.2)
> dat3<-c(3.4,NA,NA,NA,NA,NA,NA,4.1,NA,NA,NA,NA,NA,4.7)
> ta<-cbind(yr,doy,dat1,dat2,dat3)
>  
>  
> 
>   [[alternative HTML version deleted]]
> 
> __
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>

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[R] Interpolation in time

2005-10-06 Thread Anette Nørgaard 
This is exactly what I requested, thank you!! However I do actually have
several columns in my data sheet where I need to do the same thing, then
how do I come about that?
 
e.g.
 
yr<-c(rep(2000,14))
doy<-c(16:29)
dat1<-c(3.2,NA,NA,NA,NA,NA,NA,5.1,NA,NA,NA,NA,NA,4.6)
dat2<-c(2.2,NA,NA,NA,NA,NA,NA,6.1,NA,NA,NA,NA,NA,4.2)
dat3<-c(3.4,NA,NA,NA,NA,NA,NA,4.1,NA,NA,NA,NA,NA,4.7)
ta<-cbind(yr,doy,dat1,dat2,dat3)
 
 

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Re: [R] Interpolation in time

2005-10-06 Thread jim holtman 
Is this what you want?
 > yr<-c(rep(2000,14))
> doy<-c(16:29)
> dat<-c(3.2,NA,NA,NA,NA,NA,NA,5.1,NA,NA,NA,NA,NA,4.6)
> ta<-cbind(yr,doy,dat)
> ta
yr doy dat
[1,] 2000 16 3.2
[2,] 2000 17 NA
[3,] 2000 18 NA
[4,] 2000 19 NA
[5,] 2000 20 NA
[6,] 2000 21 NA
[7,] 2000 22 NA
[8,] 2000 23 5.1
[9,] 2000 24 NA
[10,] 2000 25 NA
[11,] 2000 26 NA
[12,] 2000 27 NA
[13,] 2000 28 NA
[14,] 2000 29 4.6
> good <- !is.na(ta[,'dat'])
> x.f <- approxfun(ta[good,'doy'], ta[good,'dat'], rule=2)
> ta[!good, 'dat'] <- x.f(ta[!good, 'doy'])
> ta
yr doy dat
[1,] 2000 16 3.20
[2,] 2000 17 3.471429
[3,] 2000 18 3.742857
[4,] 2000 19 4.014286
[5,] 2000 20 4.285714
[6,] 2000 21 4.557143
[7,] 2000 22 4.828571
[8,] 2000 23 5.10
[9,] 2000 24 5.016667
[10,] 2000 25 4.93
[11,] 2000 26 4.85
[12,] 2000 27 4.77
[13,] 2000 28 4.68
[14,] 2000 29 4.60
>


 On 10/6/05, Anette Nørgaard <[EMAIL PROTECTED]> wrote:
>
> Can anybody help me write a code on the following data example, which
> fills out all NA values by using a linear interpolation with the two
> closest values?
>
> Doy is day of year (%j).
>
> Code example:
> yr<-c(rep(2000,14))
> doy<-c(16:29)
> dat<-c(3.2,NA,NA,NA,NA,NA,NA,5.1,NA,NA,NA,NA,NA,4.6)
> ta<-cbind(yr,doy,dat)
>
> ta
> yr doy dat
> [1,] 2000 16 3.2
> [2,] 2000 17 NA
> [3,] 2000 18 NA
> [4,] 2000 19 NA
> [5,] 2000 20 NA
> [6,] 2000 21 NA
> [7,] 2000 22 NA
> [8,] 2000 23 5.1
> [9,] 2000 24 NA
> [10,] 2000 25 NA
> [11,] 2000 26 NA
> [12,] 2000 27 NA
> [13,] 2000 28 NA
> [14,] 2000 29 4.6
>
> Anette Norgaard
>
> [[alternative HTML version deleted]]
>
> __
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
>



--
Jim Holtman
Cincinnati, OH
+1 513 247 0281

What the problem you are trying to solve?

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[R] Interpolation in time

2005-10-06 Thread Anette Nørgaard 
Can anybody help me write a code on the following data example, which
fills out all NA values by using a linear interpolation with the two
closest values?
 
Doy is day of year (%j).
 
Code example:
yr<-c(rep(2000,14))
doy<-c(16:29)
dat<-c(3.2,NA,NA,NA,NA,NA,NA,5.1,NA,NA,NA,NA,NA,4.6)
ta<-cbind(yr,doy,dat)
 
ta
  yr doy dat
 [1,] 2000  16 3.2
 [2,] 2000  17  NA
 [3,] 2000  18  NA
 [4,] 2000  19  NA
 [5,] 2000  20  NA
 [6,] 2000  21  NA
 [7,] 2000  22  NA
 [8,] 2000  23 5.1
 [9,] 2000  24  NA
[10,] 2000  25  NA
[11,] 2000  26  NA
[12,] 2000  27  NA
[13,] 2000  28  NA
[14,] 2000  29 4.6
 
Anette Norgaard 

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