Re: subset plots in NCL

Hi Prabhakar,

It sounds like maybe you have res_at_tfDoNDCOverlay set to True. If you
do, then NCL assumes you have set up the map plot to match exactly the
area of the data grid, and it draws the data grid within those map
limits. It will not try to subscript your data in any fashion.

If you want to zoom in on your map area and have the data be
subscripted automatically as well, then you need to provide lat/lon
coordinates that are associated with your data. You can do this with
either 1D coordinate arrays or 2D lat/lon coordinates that are the
same dimensions as your data array.

Other NARR examples that we have indicate that 2D lat/lon coordinates
are available, in which case you can attach them to your data array
using the special "lat2d", "lon2d" attribute names:

    data_at_lat2d = f->lat
    data_at_lon2d = f->lon

    ...
    plot = gsn_csm_contour_map(wks,data,res)

Now, if you zoom in on the map, the data will be subscripted
appropriately.

If you do the above, then you need to make sure "tfDoNDCOverlay" is
either not set, or else set it to False. (I think all of our NARR
examples use the res_at_tfDoNDCOVerlay = True method, but the lat2d/lon2d
method would work as well.)

--Mary

On Tue, 9 Sep 2008, prabhakar shrestha wrote:

> I tried to subset NARR , RUC data while plotting using NCL but when I set
> 'mpLimitmode' to "LatLon", it plots the image with the lat lon conrner i
> specify but instead of subsetting the data its plotting the whole dataset
> within the boundaries I specified.
> Any suggestions would be higly appreciated.
> Regards,
> Prabhakar
>
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Received on Tue Sep 09 2008 - 14:07:34 MDT