[ncl-talk] how to take area average of a user-defined polygon region

[mberdahl at envsci.rutgers.edu]

Hi all,

I have model output for the north atlantic/greenland region and I would
like to take regional averages of precipitation.  I'm wondering how to
define the regions with NCL.  For example, I would like to take the
average of precipitation over the Southeast of Greenland, this region
would have to be a polygon defined by the user.  I would only like to
consider grid cells on land as well.  Does anyone have any advice on this?

Independent of this, I would like to be able to choose the grid cell
closest to a lat/lon point that is user-defined.  Can someone point me in
the right direction please?

Thanks very much,
Mira