Re: Zoom-in drawing from WRF

Hi Samuel,

When you set the tfDoNDCOverlay resource to True, you are telling NCL that
the contours should be overlaid exactly on whatever map projection you set up.
No lat/lon information is given to indicate where the contours should be overlaid
on the map; instead, NCL basically lines up the contour plot with the map plot as is.

If you zoom in on the map, then, NCL will overlay the contours to fit the zoomed
area, because that's what you are telling it to do when you set tfDoNDCOverlay to True.

What needs to happen is to *not* set tfDoNDCOverlay to True, and to include the 2D lat/lon
coordinates with the contour plot, so that NCL knows where to properly overlay the
contours on the zoomed in map. This might be a bit tricky with the wrf_xxxx functions

I can help with this if you can upload your script and data file to ftp.cgd.ucar.edu that would help:

    ftp ftp.cgd.ucar.edu
    <log in as "anonymous">
    <Use email address as password>
    cd incoming
    put <your files>
    quit
    
I'll need to know the exact name of the files in order to retrieve them.

Thanks,

--Mary

On Jan 7, 2011, at 1:11 AM, Leung Samuel wrote:

> Dear NCL Team,
>
> I am working on extracting total precipitation data from WRF and make a plot with the help of NCL script adopted from web (http://www.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/Examples/PRECIP/wrf_Precip.htm). The script worked fine when I was about to make a full domain plot, but the problem appeared when I had a zoomed view. The contour data failed to align to the basemap lat/lon. The same problem persisted when I kept the full domain plot but I changed it to mercator projection. I guess the causes of the problems for the above behaviours are the same. Certain settings about WRF map overlays have to be done.
>
> I only modified a few of the NCL script from the mentioned web, except that I only made a plot on total precipitation, and I added some codes for changing the projection and lat/lon corners:
> mpres@mpProjection = "Mercator"
> mpres@mpDataSetName = "Earth..1"
> mpres@mpDataBaseVersion = "HighRes" ; "Ncarg4_1"
>
> mpres@mpLimitMode = "Corners"
> mpres@mpLeftCornerLatF = 20.0
> mpres@mpLeftCornerLonF = 116.0
> mpres@mpRightCornerLatF = 26.0
> mpres@mpRightCornerLonF = 124.0
>
> mpres@tfDoNDCOverlay = True
>
> I would like to keep the approach of using "wrf_contour" and "wrf_map_overlays" in the NCL script. Is it possible to do that?
>
> Please let me know if you want to take a look at my whole script and tell me where I can upload it. Thanks a lot!
>
> Regards,
> Samuel Leung
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Received on Fri Jan 7 11:12:05 2011