masking

Clark, Douglas B dbcl at CEH.AC.UK
Tue Oct 27 08:35:03 EDT 2009


Sachin,

You can use the maskout function to do this kind of thing, e.g.
'd maskout(no2,india_mask)'

but you first need to create a variable (india_mask in my example) that you can use to discriminate between points in India and the rest of your domain. If you don't have such a mask available, you'll have to create one, probably outside of GrADS (e.g. using FORTRAN).

See the GrADS website for details of maskout.

For example, your india_mask variable would have value 1 over India and some value <0 at all other locations. Maskout needs a field that is <0 at the points to be excluded.

Doug


>> -----Original Message-----
>> From: GRADSUSR at LIST.CINECA.IT [mailto:GRADSUSR at LIST.CINECA.IT] On
>> Behalf Of Sachin Ghude
>> Sent: 27 October 2009 12:23
>> To: GRADSUSR at LIST.CINECA.IT
>> Subject: masking
>>
>> Hi,
>>
>> I want to plot tropospheric NO2 only over the Indian grid points (not
>> Nepal, Pakistan
>> and BanglaDesh). Is there any such utility so that it will enable me
>> to plot data only
>> for  India girds in GRADs. ( my grid size is 0.25 x 0.25 degrees).
>>
>> please do the needful..
>>
>> bye..
>>
>> Sachin

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