difference between two files

[Arlindo da Silva]

On Tue, Feb 2, 2010 at 8:26 AM, Gisele Zepka <gzepka at dge.inpe.br> wrote:

> Hello users!!
>
> I have two files with different resolutions and I want to compare the
> differences between them. I used the regrid function to take both in the
> same resolution. The regrided file is just one hour, while in the other I
> have a range of 22 times. I want to compare just the hour of the first, so I
> have two problems when I try to do that: an error of resolution, because the
> two files don't have the same quantity of points in x and y and I don't know
> how to set the time just for the second and then calculate the difference.
>
>
I am not sure I understand exactly what your problem is. First step is to
get the 2 files in the same horizontal grid. This means the same number of
points and same origin. Same grid. You can do that with the re() function
that comes with the opengrads bundle:

    http://opengrads.org/doc/udxt/re/

For the sake of argument let's say that you have done the regridding and
prepared 2 files on the same grid. Then open the 2 files

ga-> open file1
ga-> open file2

To compare variables valid at different times explicitly specify the
t-index, e.g.,

ga-> d var.2(t=3) - var.1(t=1)

  Good Luck,

     Arlindo







> Please any help will be nice!
>
> Thanks,
> Gisele
>
>
> --
> Msc. Gisele dos Santos Zepka
> Atmospheric Electricity Group (ELAT)
> National Institute for Space Research (INPE)
> Av. dos Astronautas, 1758
> São José dos Campos/ SP/ Brazil CEP 12227-010
> Phone ++55(12)39456841
>



-- 
Arlindo da Silva
dasilva at alum.mit.edu
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