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Re: [ferret_users] Changing variable's grid



Hi all,
happily, this grid is a rectangular grid utmost.
It means that there are four kinds of a delta: dx1,dx2 and dy1,dy2.
But in the end the gird is rectangular. Differences between dx1 and dx2 is as so small as I treat them as one size (fifth place after decimal point). The same is with dy1, dy2.
Hmm, I see that what you have done is to replace time axis one by another. And the first is with missing axis label, meanwhile the second has it.

Thank you all.

greetings,
Szymon Roziewski



2011/4/19 Steve Hankin <Steven.C.Hankin@xxxxxxxx>


On 4/19/2011 9:18 AM, Ansley Manke wrote:
Hi Szymon -
Olivier's solution sounds just fine, but do check in your original dataset.  Are there 2D variables that represent longitude and latitude? If so, the data is on a curvilinear grid, and you can look in the Ferret Users Guide for more details about handling data on such grids.

Hi Szymon et. al.,

I second Ansley's point:  check whether this is a curvilinear grid.

If not, then here is another approach to fixing the problem.   Using "g=final_grid@ASN" is satisfactory, too.  The following method, though, is particularly well suited to mending a flaw in a netCDF dataset, without actually altering the dataset.  The essence of the solution is to replace the erroneous axis coordinates with the correct axis definition.  In the example just below, I use the technique to replace a (valid) monthly axis with a (contrived) hourly time axis.  My example -- in which I appear to corrupt a valid file -- illustrates why the technique should be applied carefully.

    - Steve
yes? use coads_climatology
yes? show grid sst
    GRID GSQ1
 name       axis              # pts   start                end
 COADSX    LONGITUDE          180mr   21E                  19E(379)
 COADSY    LATITUDE            90 r   89S                  89N
 normal    Z
 TIME      TIME                12mr   16-JAN 06:00         16-DEC 01:20
yes? set view upper
yes? plot/x=180/y=0 sst
yes? define axis/t=0:12:1/unit=hours TIME
Replacing definition of axis TIME
 *** NOTE: grid  used by data set coads_climatology
 *** NOTE: Redefinition may alter apparent contents of data set
yes? set view lower
yes? plot/x=180/y=0 sst





Ansley


On 4/19/2011 7:55 AM, Szymon Roziewski wrote:
Thank you very much for your solution.

It works well know.

I appreciate your quick responses.

Martin:
Thank you for your wider explanation of the problem.

Best wishes,
Szymon Roziewski

2011/4/19 Olivier Marti <olivier.marti@xxxxxxxxxxxx>

Le 19 avr. 2011 à 15:55, Szymon Roziewski a écrit :

> Hello there,
>
> I am wondering if it's possible to change the grid for a defined variable?
> I mean that e.g. I have tmp variable on grid (132,145) -- elements of this grid are integers
> and eventually I want it to be on grid 132,145 but with elements defining longitudes and latitudes (real numbers).
> It's simple but I can't do it in ferret.
>
> Sth like that
> tmp = tmp[g=final_grid] doesn't work and I know why but how to do..?


If I undersand well your needs, you should use @ASN transform, and not use recursive definition of variables :

tmp2 = tmp[g=final_grid@ASN]

Olivier

--
Dr. Olivier Marti  - mailto:olivier.marti@xxxxxxxxxxxx
Laboratoire des Sciences du Climat et de l'Environnement
Institut Pierre Simon Laplace
Laboratoire CEA-CNRS-UVSQ  -  UMR 8212
Tel : +33 1 69 08 77 27 - Mob : +33 6 45 36 43 74
Fax: +33 1 69 08 30 73
<http://www.lsce.ipsl.fr/Pisp/56/olivier.marti.html>











--
Z wyrazami szacunku,
Szymon Roziewski



--
Z wyrazami szacunku,
Szymon Roziewski

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