[ncl-talk] Add polyline, polygon, and polytext to a map generates two PNG files.

[Adam Phillips]

Hi Wei,
I have created a sample test script that draws a blank map, and adds a
polyline, polymarker, and some text to a specific location on the map. I've
attached the script and resulting png.

Note that with all the gsn_add_* functions you have to keep the resulting
output array from the gsn_add_* functions. From the gsn_add_polyline
documentation:

"The value(s) returned from this function must be assigned to a unique
variable. This is necessary so that the polyline(s) "live" for the duration
of the NCL script. This is especially imperative if the call to
*gsn_add_polyline* is inside a function or procedure."
https://www.ncl.ucar.edu/Document/Graphics/Interfaces/gsn_add_polyline.shtml

In my test script I assigned the output to dum0, dum1 and dum2. I could
have created an array: dum = new(3,graphic) and assigned the output to
dum(0), dum(1) and dum(2).. Either way, I cannot delete or overwrite the
output arrays (dum or dum0, dum1, dum2)..

Hope that all makes sense!
Adam


On Tue, Jul 14, 2015 at 12:18 PM, Wei Huang <whuang at univ-wea.com> wrote:

>  Adam,
>
>
>
> I used gsn_add_* suite for the polylines, polygons, polytexts.
>
>
>
> If I set:
>
>    res                      = True
>
>    res at gsnDraw              = False
>
>   res at gsnFrame             = False
>
>
>
> It can turn off (eliminate) the blank map, but later, there are a whole
> bunch of warning msgs,
>
>
>
> warning:gsnDraw/gsnFrame is not a valid resource in graphic_style at this
> time.
>
>
>
> This make it hard to read other msgs.
>
>
>
> Thanks,
>
>
>
> *Wei Huang*
>
>
>
> *From:* Adam Phillips [mailto:asphilli at ucar.edu]
> *Sent:* Tuesday, July 14, 2015 1:07 PM
> *To:* Wei Huang
> *Cc:* ncl-talk at ucar.edu
> *Subject:* Re: [ncl-talk] Add polyline, polygon, and polytext to a map
> generates two PNG files.
>
>
>
> Hi Wei,
>
> It depends on what functions/procedures you are using to draw your
> polylines/markers/text.. In all cases you should set gsnFrame = False in
> your res resource list.
>
> I prefer the gsn_add_* suite of functions to do what you are doing as it
> allows paneling. For those functions you also need to add gsnDraw = False
> to your res resource list.
>
> If you are just using gsn_text/gsn_polygon/gsn_polygon you can get away
> with not setting gsnDraw as is shown in polygon example #8 here:
> https://www.ncl.ucar.edu/Applications/Scripts/polyg_8.ncl
>
>
>
> Hope that helps!
>
> Adam
>
>
>
>
>
>
>
>
>
>
>
> On Tue, Jul 14, 2015 at 10:05 AM, Wei Huang <whuang at univ-wea.com> wrote:
>
> I am trying to add polyline, polygon, and polytext to a map, steps as
> below:
>
>   res = ...
>   wks = ...
>    map = gsn_csm_map(wks, res)
>
>  ;add lots of polylines, polygons, and polytexts to map
>
> draw(map)
>  frame(wks)
>
> It generates two PNG files. With the first just a map.
>
> How can I remove the first blank map?
>
> Thanks,
>
> Wei Huang
> whuang at univ-wea.com
>
>
> _______________________________________________
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>
>
>
>
> --
>
> Adam Phillips
>
> Associate Scientist,  Climate and Global Dynamics Laboratory, NCAR
>
> www.cgd.ucar.edu/staff/asphilli/   303-497-1726
>
>
>



-- 
Adam Phillips
Associate Scientist,  Climate and Global Dynamics Laboratory, NCAR
www.cgd.ucar.edu/staff/asphilli/   303-497-1726

<http://www.cgd.ucar.edu/staff/asphilli>
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