Re: Zoom-in drawing from WRF

From: Leung Samuel <shwl0608_at_nyahnyahspammersnyahnyah>
Date: Sun Jan 09 2011 - 18:21:03 MST

Dear Mary,

I uploaded two files, the NCL script and the WRF output data (in gz format,
please gunzip it and rename it to *.nc before running the script). Please
check if the files mentioned exist, as I am not able to see them after

Thanks for your help!

Samuel Leung

On Sat, Jan 8, 2011 at 2:11 AM, Mary Haley <> wrote:

> 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
> that would help:
> ftp
> <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 (
> 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 Sun Jan 9 18:21:14 2011

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