[R] take data from a file to another according to their correlation coefficient

jeff6868 geoffrey_klein at etu.u-bourgogne.fr
Mon Apr 23 12:42:29 CEST 2012


Hi everyone.

I have a question about a work on R I have to do for my job.
I have temperature data coming from 70 weather stations. One data file
corresponds to one station for one year (so 70 files for one year). Each
file looks like this (important: each file contains NAs):

time                          data
01/01/2008 00:00 -0.25 
01/01/2008 00:15 -0.18 
01/01/2008 00:30 -0.25 
01/01/2008 00:45 -0.25 

(one column with date + time every 15mn for the whole year, and one column
with data). 

I already did correlation matrices between my weather stations (in order to
find the nearest). For example:

                  Station1 Station2 Station3 [...]
Station1        1              0.9            0.8
Station2        0.9             1             0.7
Station3        0.8           0.7             1
[...]

Now, I would like to fill the NA data gaps of a station with data from
another station according to their correlation coefficient.
Let's take an example for the Station 1: if the most correlated Station with
Station 1 is Station 2, it has to take data from Station 2 to fill NA gaps
of Station 1, for the same date and hour of course (or same lines as I'm
doing correlations for the same year). 
So for year 2008 (for example), if the correlation is the highest between
Station 1 and 2 (according to all the Stations), and if the data are:

time                            data
01/01/2008 00:00   1
01/01/2008 00:15   2       FOR STATION 1
01/01/2008 00:30   *NA* 
01/01/2008 00:45   4 

and 

time                            data
01/01/2008 00:00   8
01/01/2008 00:15   9          FOR STATION 2 for the same year and the same
time
01/01/2008 00:30   *10 *
01/01/2008 00:45   11

The Station1 file should become:

time                            data
01/01/2008 00:00   1
01/01/2008 00:15   2       STATION 1
01/01/2008 00:30   *10 *
01/01/2008 00:45   4 

Hope you've understood what I would like to do :)
Thanks a lot for your ideas and your replies!






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