Re: Output a NetCDF Mask Based on Geographic Areas

From: <Maurice.McHugh_at_nyahnyahspammersnyahnyah>
Date: Tue Jan 05 2010 - 10:21:18 MST

How about using a digital elevation model database (i.e. http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/gtopo30_info) in netCDF format? Use the NCL "where" function to assign 1's and 0's to land and water to generate the land/sea mask. If you write the mask to a file you can then reuse the mask as required.

Global DEM data in netCDF at various resolutions an be found here: http://users.ictp.it/~pubregcm/RegCM3/globedat.htm#part5

Maurice

----- Original Message -----
From: Mary Haley <haley@ucar.edu>
Date: Tuesday, January 5, 2010 12:11 pm
Subject: Re: Output a NetCDF Mask Based on Geographic Areas
To: Scott Capps <scapps@atmos.ucla.edu>
Cc: ncl-talk@ucar.edu

> Hi Scott,
>
> I'm afraid it is not possible to interact with the NCL map databases
>
> in this fashion. We've had requests for this kind of thing, and it's
>
> on our to do list.
>
> You might look at the landsea_mask function:
> Document/Functions/Shea_util/landsea_mask.shtml
>
> You would have to provide the lat/lon arrays of your geographic area.
>
> Perhaps they are available in a shapefile, which NCL does support.
>
> For some general masking examples, please see:
>
>
>
> This page might give you some ideas on what you are trying to
> accomplish.
>
> --Mary
>
> On Jan 4, 2010, at 11:53 AM, Scott Capps wrote:
>
> > Greetings,
> >
> > I was wondering if there is a way to create a netCDF mask file with
>
> > one's and zero's corresponding to a geographic areas specified
> > using the Earth..4 map data set?
> >
> > The mask_4.ncl example on the NCL website is great for plotting.
> > However, I want to create a mask netCDF file based on geographic
> > areas. Is this possible?
> >
> >
> > Thank you,
> >
> >
> > Scott
> >
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Received on Tue Jan 5 10:21:40 2010

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