[ncl-talk] How do I get North to be Up For my Plots of WRF Data?

Ronald Stenz rds238 at cornell.edu
Tue Feb 13 15:04:01 MST 2018

Great, thanks!  Yes, I was using wrf_map_overlays and was trying
unsuccessfully to plot as a different map projection from the WRF file.
I'll modify my codes like the link you provided and that should fix it.
Thanks for the help!

On Tue, Feb 13, 2018 at 3:57 PM, Mary Haley <haley at ucar.edu> wrote:

> Ronald,
> As Barry mentioned, it would help if we could see your script and a sample
> image. When you say north is "up and right" this sounds like you might have
> some kind of rotated lat/lon projection.
> Also, are you using the wrf_contour, wrf_vector, and/or wrf_map_overlays
> to plot your data? If so, then be aware that these functions use whatever
> native map projection is defined on your WRF file, and you will not be able
> to change this.
> If you want to change the map projection, then you need to use either the
> gsn_csm_contour_map or gsn_csm_vector_map function, depending on whether
> you are drawing contours or vectors, *and* you will need to provide the lat
> / lon coordinates to these functions via the special lat2d / lon2d
> attributes.
> You can see some examples of using the wrf_xxxx functions versus the
> gsn_csm_xxxx_map functions at:
> http://www.ncl.ucar.edu/Applications/wrfgsn.shtml
> In particular, look at the the first example, wrf_gsn_1.ncl and
> wrf_nogsn_1.ncl.  In the wrf_gsn_1.ncl example, you'll see how it reads the
> XLAT / XLONG variables off the WRF file and attaches them to the "hgt"
> variable, via:
>   hgt at lat2d = wrf_user_getvar(a,"XLAT",it)   ; latitude/longitude
>   hgt at lon2d = wrf_user_getvar(a,"XLONG",it)  ; required for plotting
> By doing this, you can choose whatever map projection you want. This
> particular example uses a simple lat/lon projection, also known as a
> cylindrical equidistant projection.
> --Mary
> On Sun, Feb 11, 2018 at 7:58 PM, Ronald Stenz <rds238 at cornell.edu> wrote:
>> I must be missing something simple, but I can't figure out how to get
>> North to be Up for my WRF plots.  Currently, no matter what I do, north
>> always ends up being towards the upper right in my plots (regardless of
>> what map projection I use).  I just looked to provide the link for where I
>> got the base NCL plotting codes, but I can't seem to find it anymore on
>> google and it looks like newer versions of codes now exist?  Will switching
>> to these new NCL graphics codes for WRF allow me to do this, or is this
>> something that should work with the codes I already have?
>> If so, how do I get North to be Up in my plots, and not up and right?
>> Thanks
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