[ncl-talk] plotting a polygon over an existing plot

[Rashed Mahmood]

Hi Alison,
It is difficult to answer the question without data file, but I just
noticed that you may need to switch your xpts and ypts in the call to
gsn_add_polyline.
So replace the line:

From:
        dum(i) =
gsn_add_polyline(wks,contour_tot,xpts(i:i+1),ypts(i:i+1),resp)
To:
        dum(i) =
gsn_add_polyline(wks,contour_tot,ypts(i:i+1),xpts(i:i+1),resp)

I not sure if this would solve the issue because I do not have experience
in WRF related plotting.

Cheers,
Rashed




On Tue, Jul 31, 2018 at 4:02 PM, Alison Bridger <alison.bridger at sjsu.edu>
wrote:

> Ooops - wtest.ncl attached!
>
> Another way to state my problem is by looking at the sample code under
> gsn_add_polygon
>
> The quantities dum1, dum2, and dum3 are defined (left of equals sign) but
> I don't see them again in the code, so how are they used???
>
> On Tue, Jul 31, 2018 at 2:06 PM Alison Bridger <alison.bridger at sjsu.edu>
> wrote:
>
>> Although my NCL skills are gradually improving, I am still stumped by
>> simple tasks!
>>
>> The attached code reads in WRF output, extracts rainfall, sums it over
>> the run, and contour plots the total each hour. I got it from somebody else
>> here!
>>
>> I want to superimpose ("overplot") small columns at a few locations
>> showing obs versus WRF rain totals. So imagine - say - small red and blue
>> columns side-by-side somewhere on this plot (e.g., SFO) showing obs and WRF
>> rain totals.
>>
>> I have spent 2 hours (!) trying to morph the sample code in polyg_4.ncl
>> (from the NCL pages) into my code (wtest.ncl, attached), but I get nothing
>> visual and no useful diagnostics.
>>
>> I fell this is related to things like "frame" and "draw" and "plot" and
>> so forth, but no amount of trying seems to make me understand how these
>> relate to each other!
>>
>> The added code starts near the end with "xpts = ...".
>>
>> Thanks for any pointers!
>>
>> Alison
>>
>> PS can supply wrfout file if needed
>>
>> --
>>
>>                  Alison F.C. Bridger
>>                   Professor & Chair
>>
>>     Department of Meteorology and Climate Science
>>
>>     San Jose State University      tel  408.924.5206
>>     One Washington Square          fax  408.924.5191
>>     San Jose, CA 95192-0104
>>
>>              email:   Alison.Bridger at sjsu.edu
>>
>>        *Global CO2 levels...410 ppm and still rising*
>>
>>
>>                  www.sjsu.edu/meteorology <http://www.met.sjsu.edu>
>>
>>
>
> --
>
>                  Alison F.C. Bridger
>                   Professor & Chair
>
>     Department of Meteorology and Climate Science
>
>     San Jose State University      tel  408.924.5206
>     One Washington Square          fax  408.924.5191
>     San Jose, CA 95192-0104
>
>              email:   Alison.Bridger at sjsu.edu
>
>        *Global CO2 levels...410 ppm and still rising*
>
>
>                  www.sjsu.edu/meteorology <http://www.met.sjsu.edu>
>
>
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