[ncl-talk] wind barbs in southern hemisphere

[Dennis Shea]

*wrf_vector*:

Most 'high-level' graphical interfaces set parameters and resources
*internally*.
Hence, it is quite possible that parameters set outside of the function may
not have any effect.
===

Perhaps ... untested

[1] Draw the map or a scalar over a map with gsnFrame=False
[2] Use *wmbarbmap*
<http://www.ncl.ucar.edu/Document/Functions/Built-in/wmbarbmap.shtml>

  ... drwa scaler
  *wmsetp* <http://www.ncl.ucar.edu/Document/Functions/Built-in/wmsetp.shtml>("col",
2)    ; Draw in red.
;;*wmsetp* <http://www.ncl.ucar.edu/Document/Functions/Built-in/wmsetp.shtml>("wbs",
.06)  ; Increase the size of the barb.
  *wmbarbmap*(wks, lat, lon,  u, v)  ; Plot barbs.
  *frame* <http://www.ncl.ucar.edu/Document/Functions/Built-in/frame.shtml>(wks)
         ; Advance the *frame*
<http://www.ncl.ucar.edu/Document/Functions/Built-in/frame.shtml>.


On Sun, Jun 2, 2019 at 1:37 PM Zilore Mumba <zmumba at gmail.com> wrote:

> Rick,Thank you very much. That command has no effect. The ncl command I am
> using is: vector = wrf_vector(a,wks,u_plane,v_plane,opts). I have tried the
> plotting commands used in barb_1.ncl
> <https://www.ncl.ucar.edu/Applications/Scripts/barb_1.ncl> and barb_2.ncl
> <https://www.ncl.ucar.edu/Applications/Scripts/barb_1.ncl>, both give
> errors. This is because the way these two extract the u- and v-wind
> components differs from the function I use.
> I think the plotting funcion could be at the heart of my problem. I will
> see how I can modify my script to use the barb_1.ncl plotting function.
>
>
> Thank you very much for your time, and for the hint.
>
> On Sat, Jun 1, 2019 at 10:36 PM Rick Brownrigg <brownrig at ucar.edu> wrote:
>
>> Hi Zilore,
>>
>> Yes, as cryptic as the line "*wmsetp*
>> <http://www.ncarg.ucar.edu//supplements/wmap/index.html#HEADING1-225>("wba",-62.0)"
>> seems, perhaps try that if you haven't already. I personally am not sure
>> how that's supposed to work, but Dennis must have some insight on that.  To
>> answer your question about what it all means, parts of NCL make use of a
>> lower-level software package called WMAP. NCL does a pretty good job of
>> setting parameters to that package, but wmsetp() is a means by which a user
>> can override those settings and control WMAP directly. The parameters that
>> one can override -- and the meaning of the "wba" parameter -- can be found
>> here:
>>
>>     http://www.ncarg.ucar.edu//supplements/wmap/index.html#HEADING1-225
>>
>> and general information about WMAP can be found here:
>>
>>     http://www.ncarg.ucar.edu//supplements/wmap/index.html
>>
>> BTW: what NCL function are you calling to draw the wind barbs?
>>
>> --Rick
>>
>> On Sat, Jun 1, 2019 at 10:57 AM Zilore Mumba <zmumba at gmail.com> wrote:
>>
>>> I have rerun my WRF over a domain which goes across the equator. There
>>> is no change in the barbs north and south of the equator. I am interested
>>> in the command: *wmsetp*
>>> <http://www.ncarg.ucar.edu//supplements/wmap/index.html#HEADING1-225>("wba",-62.0)
>>>                    ; NH (default) is 62.0
>>> How is it used? Is it simply that line?
>>> Thanks
>>>
>>> On Fri, May 31, 2019 at 9:37 PM Dennis Shea <shea at ucar.edu> wrote:
>>>
>>>> Hopefully, somebody who knows about WRF graphics will respond.
>>>>
>>>> --
>>>> Perhaps, *before calling the WRF graphics*, try the low level NCAR
>>>> Graphics option:
>>>>
>>>>    *wmsetp*
>>>> <http://www.ncarg.ucar.edu//supplements/wmap/index.html#HEADING1-225>("wba",-62.0)
>>>>                    ; NH (default) is 62.0
>>>>
>>>> On Fri, May 31, 2019 at 1:20 PM Zilore Mumba <zmumba at gmail.com> wrote:
>>>>
>>>>> Dennis,
>>>>> Thanks very much. I have seen that barbs are drawn correctly for he
>>>>> southern and northern hemispheres on the link you gave.
>>>>>  I am drawing WRF output. My domain is entirely in the southern
>>>>> hemisphere but barbs are on the left. I use one of the sample wrf scripts
>>>>> which plots several levels in one script, though now I cannot remember
>>>>> which one.
>>>>> The barb color change works.
>>>>> Once more, thank you very much.
>>>>>
>>>>> On Fri, May 31, 2019 at 4:14 PM Dennis Shea <shea at ucar.edu> wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> [1]* http://www.ncl.ucar.edu/Applications/barb.shtml*
>>>>>> <http://www.ncl.ucar.edu/Applications/barb.shtml>
>>>>>>
>>>>>> If you are plotting over  grid, the Northern/Southern Hemisphere wind
>>>>>> barbs are *automatically* drawn to the left/right.
>>>>>> See the main figure, entitled "Default Wind Barbs"
>>>>>>
>>>>>> [2] vc resources:
>>>>>>
>>>>>>      vcMonoWindBarbColor=True  ; this is the default
>>>>>>
>>>>>> *vcWindBarbColor="red"      ; wind barb color*
>>>>>>
>>>>>> On Fri, May 31, 2019 at 4:48 AM Zilore Mumba <zmumba at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Dear all,
>>>>>>> especially the managers at ncl, I have two questions:
>>>>>>> 1. My wind barbs are drawn to the left of the wind, facing
>>>>>>> downstream. I am in the southern hemisphere where we have to have barbs to
>>>>>>> the right.
>>>>>>> 2. Is it possible to have barbs all red, or all any color. I have
>>>>>>> only seen colored by a scalar.
>>>>>>> hank you.
>>>>>>> _______________________________________________
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>>
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