Re: extracting the netCDF data within the polygon path (ascii)

[Ansley Manke <ansley@xxxxxxxxxxxxx>]

Hi,
Welcome to the Ferret community.  You want the SAMPLEXY
function.  There is an example in the Users Guide that shows how
to use it.  Look at  "SAMPLEXY, defined" in the Users Guide at
http://ferret.pmel.noaa.gov/Ferret/Documentation/Users_Guide/current/fer_html.htm

Here are the basic steps:

Open the data set to be sampled.  To read your ascii
file, you can use the FILE command.

  USE levitus_climatology
  FILE/VAR="xpts,ypts" data2.dat
  SHOW data

  ! List the surface temperature at the points
  LIST/K=1 SAMPLEXY(temp[d=1], xpts, ypts)

  ! Plot the temperature at each depth.  The horizontal
  ! axis is sample point number, an abstract axis.

  SHADE  SAMPLEXY(temp[d=1], xpts, ypts)


Ansley Manke


Dong-Ha Min wrote:

> Hello.
>
> I want to extract the data from a netCDF-format file for a specific
> geographic region defined by the irregular-shape polygon paths in a
> separate ascii file. Can someone guide me step by step how to do this?
>
> For example, say, I have a levitus_climatology.cdf (data 1) and want to
> extract the sea surface temperature from the region given by data 2 (see
> below).
>
> data2 (lon, lat)
> ---------------
> 160.5 20.5
> 160.5 30.5
> 170.5 30.5
> 170.5 20.5
> 160.5 20.5
>
> I am a beginner of ferret, so forgive me if this is a trivial task.
>
> Many thanks in advance.
>
> Cheers,
> Dong-Ha Min

--
Ansley Manke  Pacific Marine Environmental Laboratory  Seattle WA  (206)526-6246