Re: Question about picking a region

From: Alessandra Giannini <alesall_at_nyahnyahspammersnyahnyah>
Date: Sun Feb 06 2011 - 21:07:51 MST

Dennis, Eddy,

I think it may be a bit more complicated, but correct me if I am wrong...

Longitudes in the dataset of interest go between -180 and 180 and you need to
include points between 150 and 180, and between -180 and -120. These two sets
are not contiguous.

I do something like this - you need to first mask your "lon" vector,
and then select your x variable on the masked lon values:

   masklon = mask(lon,lon.ge.150.and.lon.le.-120,True)
   lonindx = lon(ind(masklon.gt.-999))

and then

y = x(... {lon | lonindx})

Hope this helps!
best, alessandra

----- Original Message -----
From: Dennis Shea <shea@ucar.edu>
To: eddycarl <eddycarl@126.com>
Cc: ncl-talk <ncl-talk@ucar.edu>
Sent: Sun, 6 Feb 2011 22:43:37 -0500 (EST)
Subject: Re: Question about picking a region

  latS = -30.0
  latN = 30.0
  lonL = -120.0 ; <====
  lonR = 150.0 ; <====
y = x(:,{latS:latN},{lonL:lonR})

If you are not reshaping you do not need to explicitly
name the dimensions.

On 2/6/11 3:32 PM, eddycarl wrote:
> Hi there,
>
> I have a question about selecting data over a geographical region.
> Suppose that data x(time,lat,lon) is with
> lat=(-90.0,90),lon=(-179.5,179.5) at 1x1 degree resolution. If I want to
> pick a region over the Pacific ocean, such as latitude from 30N to 30S,
> longitude from 150E to 120W. What I used is
>
> latS = -30.0
> latN = 30.0
> lonL = 150.0
> lonR = -120.0
> y = x(time|:,{lat|latS:latN},{lon|lonL:lonR})
>
> However, this will produce an area actually from 120W to 150E, instead
> of over Pacific. Does anyone know what shall I do to get it right? Thanks!
>
> -Eddy
>
>
>
>
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Received on Sun Feb 6 21:08:09 2011

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