concatenation of files with different dimensions

[lal]

Hi
I have two files and the metadata for them is:

1) File1:
dimensions:
time = 20089;
lat = 5;
lon = 38;
variables:
double time(time=20089);
:units = "days since 1960-01-01 00:00:00.0 +0545";
:time_origin = "1960-01-01 00:00:00";

float rain_der_ens(time=20089, lat=5, lon=38);
  :_FillValue = -9999.0f; // float
  :missing_value = -9999.0f; // float

float longitude(lon=38);
  :units = "degrees east";

float latitude(lat=5);
  :units = "degrees north";

2) File2:
dimensions:
time = 20089;
lat = 3;
lon = 47;
variables:
double time(time=20089);
:units = "days since 1960-01-01 00:00:00.0 +0545";
:time_origin = "1960-01-01 00:00:00";

float rain_der_ens(time=20089, lat=3, lon=47);
  :_FillValue = -9999.0f; // float
  :missing_value = -9999.0f; // float

float longitude(lon=47);
  :units = "degrees east";

float latitude(lat=3);
  :units = "degrees north";

As we see the size of lat lon dimensions is different. Also some of the lat and lon values are repeated between the two files(not the lat-lon combination but individual lat or lon values). How can I concatenate files in this scenario. I have written a python script to concatenate the files but the execution time becomese too long as the size of the files to concatenate increases.

Please let me know how to handle this type of concatenation efficiently. I had tried nco operators but I think they do not handle this scenario(I hope I am wrong here).

[Charlie Zender]

Interesting question. I can't think of any elegant solutions. Anyone else?
cz

[John]

I visualize the spatial overlap to be something like this:

xxxxxxxxxx
xxxxxxxxxx
xxxxxoooooooooo
xxxxxoooooooooo
     oooooooooo
     oooooooooo

where x is file 1, and o is file 2. I would divide each file into 2 files, resulting in 4 files that lie like this:

1111122222
1111122222
111113333344444
111113333344444
     3333344444
     3333344444

a) Concat 2 with 3;
b) extend the dimensions of 1 and 4; then
c) concat 1, the result of (a), and 4.

Not elegant (rather, painful), but should work?

[lal]

Thanks John and Charlie.
John: I did not quite understand.

I have found a similar question asked on this forum: http://sourceforge.net/p/nco/discussion/9830/thread/2782cde1/

The recommendation on that thread was also an custom script to do the merging.

I have meanwhile made my script faster by writting it in c and using openmp to parallelize. So it is not bothering me anymore.