Re: [ferret_users] extract irregular grid values

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi Ninin,
You can make computations on an irregular shaped region by defining a mask, as outlined in this FAQ.  It shows one method of defining the mask based on variable values, but all that's needed is some method of generating a field on the same grid which is 1 where you want to work with data and missing otherwise:

../../faq/averaging-integrating-over-irregular-regions

Another tool is the pt_in_poly function.  If what you have is a set of locations that defines the boundary, you could use that, and then define the mask from that.

Ansley

On 5/5/2014 4:05 AM, Nitin Patil wrote:

Dear Hein,

I have a netcdf file (I cant share bz it is too big in size). We have selected region for our analysis over INDIA but our domain region is not in a proper square or rectangle shape it is in irregular shape. So i cant provide direct start and end points of latitude and longitude of the area. May be I have to indicate all grid points Lat Lon notations in the scripts to extract and save in txt format. Did you know how to specify it.

--

Regards,

Nitin Patil

On Mon, May 5, 2014 at 12:54 PM, Hein Zelle <hein.zelle@xxxxxxxxxxxxx> wrote:

Hi Nitil,

> I want to extract irregular grid values from netcdf and to be saved in
> netcdf. Does anyone have idea, please let me know.

Could you provide a little more information?  It's not clear to me
what you mean.  What kind of "irregular grid values" do you want to
extract?  Do you have an example file?

Kind regards,
     Hein Zelle

--

Dr. Hein Zelle
Senior consultant meteorology & oceanography
BMT ARGOSS

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