[R] Question re: interpolation

[Felipe Carrillo]

Are you looking for something like this?

data <- data.frame(first= c(1,2,3,4,5,6,7,8), zehn = c(15,NA,NA,NA,NA,18,NA,25),
     second = c(4,NA,7,9,NA,10.2,NA,12),
    third= c(6,7,NA,NA,10,12,NA,16))
  data
    library(zoo)
    data2 <-na.approx(data,na.rm=F)
    data2
?na.approx
 
Felipe D. Carrillo
Supervisory Fishery Biologist
Department of the Interior
US Fish & Wildlife Service
California, USA



----- Original Message ----
> From: Jessica Schedlbauer <jschedlb at fiu.edu>
> To: "r-help at r-project.org" <r-help at r-project.org>
> Sent: Sun, May 2, 2010 2:27:10 PM
> Subject: [R] Question re: interpolation
> 
> Hello,

I have a matrix in which two variables, x and y, are used together 
> to determine z.  The variables x and y are sorted into classes.  
> Specifically, values for variable x range from 0 to 2.7 and are sorted into 
> class increments of 0.15 and variable y ranges from 0-2100 with class increments 
> of 100.  For each x-y class combination, I have calculated a mean value of 
> z from existing data.  However there are gaps in the existing data (i.e., 
> x-y combinations for which there are no z data).  I would like to 
> interpolate values to fill in these missing datapoints, but have so far been 
> unable to find a straightforward way of doing so in R.  There are many gaps 
> in the data and I need to repeat this process for several individual 
> datasets.  That said, I am looking for a way to avoid interpolating each 
> missing point separately.

Any suggestions would be greatly 
> appreciated.

Regards,
Jessica 
> Schedlbauer

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