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Re: [ferret_users] extracting boundary information from a masked file


Since you're dealing with 2D fields it will be easier to build a land mask from 2D variables than a 1D lat/lon boundary.

You say that your values are over land only, are they 1D or 2D ?

If your data is 1D, first build a 2D field using a 'scat2grid*' function (do list them, try: yes? sh fun scat2grid* ), then it should be straightforward to build a land mask from your own data (let msk = if your_var then 1).

The attached script illustrates how 2D var masking works.

On Tue, 2015-10-20 at 14:05 +0530, Dhirendra Kumar wrote:
Dear Ferret Community

I have a netcdf file which has got the values over land regions only. Is there any way through which I can extract the boundary information (list of Latitude and longitude of boundary)out of it, so that other file could be masked over the same region.

Please help....

Any lead is appreciated.


Dhirendra Kumar

School of Environmental Sciences, JNU

New Delhi (India)
Contact: +91 9910778043
Alternate email: dhirendra.cub@xxxxxxxxxxx

Attachment: topo_land_ocean.png
Description: PNG image

 ! FERRET v6.93 (PyFerret 1.1.0)
 ! Linux - 12/05/14
 ! 20-Oct-15 10:40     

use etopo05

let land = if rose ge 0 then 1
let ocean = if rose lt 0 then 1

set reg/y=5:35/x=65:95

set win/asp=0.5

set viewp left; shade rose*land; go land_detail
set viewp right; shade rose*ocean; go land_detail



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