[ncl-talk] Problem with overlay procedure

[Anne]

Hi Adam,

thanks for your suggestion, however setting the opacity of the chla_plot to
semi-transparent did not solve the problem. In fact I should see both
fields without setting the opacity to semi-transparent as buff1 is slightly
larger than chla.

In any case, I realized that I do not need the 'overlay' procedure after
all, because I will have to use only one field for my mask which simply
takes on different values for different lat-lon regions.

thanks again,
Anne

On 30 May 2017 at 20:39, Adam Phillips <asphilli at ucar.edu> wrote:

> Hi Anne,
> Without being able to run your script from here, my best guess on your
> issue is that you are overlaying a color-filled contour field on a 2nd
> color-filled contour field. I would try setting the opacity of the your
> chla_plot to be semi-transparent. Add this line to your res2 resource list.
> res2 at cnFillOpacityF = 0.5
>
> The resulting plot should show both your chla and buff plots. More
> information about the various opacity resources can be found here:
> http://www.ncl.ucar.edu/Applications/rgbacolor.shtml
>
> Other minor things that I see:
> - You do not need to set sfXArray or sfYArray as your chla and buff arrays
> have attached latitude/longitude coordinate variables. You also do not need
> to set those resources in your mpres resource list as they are not needed
> when using gsn_csm_map.
> - I do not think you need to set res at cnFillDrawOrder.
> - You create a mpres resource list, and then create a res and a res2
> resource list from mpres, and that carries your map resource settings
> through to res and res2. I think simply deleting this line: res = mpres
> will get rid of many (if not all) of your error messages.
>
> If that above does not solve your plotting issue please respond to the
> ncl-talk email list.
> Adam
>
>
> On Mon, May 29, 2017 at 3:47 AM, Anne <anne.seidenglanz at unive.it> wrote:
>
>> Hi everybody,
>>
>> I have a problem overlay-ing two contour fields on a map plot (see script
>> attached). The final purpose is to mask out a specified area on a global
>> triangular grid (simply consisting of ones and zeros), and to create a
>> buffer zone around the area for physical reasons. Creating the mask itself
>> is no problem, but when I want to overlay the layers for creating the
>> buffer zone (for which each layer is just slightly bigger than the
>> following one), NCL just plots me the last overlaid field. So when I do
>> (here an example of 2 contour fields on top of each other):
>>
>>     map_plot  =  gsn_csm_map(wks, mpres)
>>     chla_plot =  gsn_csm_contour(wks, chla, res2)
>>     buff_plot = gsn_csm_contour(wks, buff, res)
>>
>>     overlay(map_plot, buff_plot)
>>     overlay(map_plot, chla_plot)
>>
>> then only 'chla_plot' is successfully overlaid on the map plot, but not
>> 'buff_plot' (which is bigger in spatial extent than 'chla'). There are some
>> error messages regarding resources that cannot be used but because I can
>> successfully plot each field on top of the map plot separately (apart from
>> the red line when plotting 'buff'), I assume they are not important.
>>
>> A few things to note:
>> 0) Both chla and buff have associated coordinate arrays.
>> 1)  gsn_csm_contour_map_overlay did not work either, it plots only 'chla'
>> and some strange contour labels for 'buff', but distorted.
>> 2)  switching off the satellite projection did not make any difference
>> 3)  I can plot each field ('chla' and 'buff') separately overlaid on the
>> map successfully
>> 4)  I have also tried to use gsn_csm_contour_map but because I can use
>> this only as my base plot, the overlaid contours (chla and buff) look
>> disorted using gsn_csm_contour.
>>
>> Anybody any idea? Any help is appreciated!
>>
>> Thanks,
>> Anne
>>
>>
>>
>>
>> "Nota automatica aggiunta dal sistema di posta.
>> Please note that the above message is addressed only to individuals
>> filing Italian income tax returns."
>>
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>
>
> --
> Adam Phillips
> Associate Scientist,  Climate and Global Dynamics Laboratory, NCAR
> www.cgd.ucar.edu/staff/asphilli/   303-497-1726 <(303)%20497-1726>
>
> <http://www.cgd.ucar.edu/staff/asphilli>
>

-- 
"Nota automatica aggiunta dal sistema di posta.
Please note that the above message is addressed only to individuals filing 
Italian income tax returns."
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