[pyngl-talk] Fill color between 2 lines with Ngl.xy

[Mary Haley]

I think the simple answer is that you need to make sure the contour fill
draw happens before the XY fill happens.

res.cnFillDrawOrder = "PreDraw"

There are three phases that various aspects of the plots get drawn in:
"PreDraw", "Draw" and "PostDraw".

If you make sure the contour fill draw happens in the "Predraw" phase, and
the XY fill in the "PostDraw" phase, then it should work.

If both things fall in the PostDraw phase, then I'm not exactly sure what
the ordering is of those elements.

I've attached a sample program and PNG file (which is not very interesting
because it uses dummy data).

--Mary


On Thu, Aug 30, 2018 at 4:57 PM, Mary Haley <haley at ucar.edu> wrote:

> Hi Matt,
>
> I'm looking into this one; I don't think we have an example in our
> gallery, but I'll try to create one to see if it works.
>
> --Mary
>
>
> On Fri, Aug 24, 2018 at 12:06 PM, Fearon, Dr. Matthew, Contractor, Code
> 7533 via pyngl-talk <pyngl-talk at ucar.edu> wrote:
>
>> Just a follow-up. I have learned that fill color between 2 adjacent lines
>> with Ngl.xy works nicely for an exclusive xy plot. However, it does not
>> work as an overlay to a contour plot when sfXArray/sfYArray or
>> sfYCStart/End/ and sfXCStart/End are used in the original contour plot.
>> Individual xy lines with Ngl.xy can be overlain on a contour plot with no
>> trouble, but fill color between them does not work.
>>
>>
>>
>> Any help on this subject would be great.
>>
>> Thanks,
>>
>> Matt
>>
>>
>>
>>
>>
>> *From:* pyngl-talk [mailto:pyngl-talk-bounces at ucar.edu] *On Behalf Of *Fearon,
>> Dr. Matthew, Contractor, Code 7533 via pyngl-talk
>> *Sent:* Thursday, August 23, 2018 12:28 PM
>> *To:* pyngl-talk at ucar.edu
>> *Subject:* [pyngl-talk] Fill color between 2 lines with Ngl.xy
>>
>>
>>
>> Hi, PyNGL Users,
>>
>>
>>
>> I’m trying to indicate the terrain profile on the attached cross section
>> plot. I am able overlay an xy line (black, terrain top) and another xy line
>> (red, ground surface), but am unable to fill color between these two lines.
>> All the combinations I have tried are not working. Below is my Ngl.xy code
>> for the overlay. Any help is greatly appreciated.
>>
>>
>>
>> Thanks,
>>
>> Matt
>>
>>
>>
>> -----
>>
>> xvar[100] is a np array of the xvalues
>>
>> pter[2,100] is a np array of the yvalues
>>
>>
>>
>>     xyres                        = Ngl.Resources()
>>
>>     xyres.nglFrame               = False
>>
>>     xyres.nglDraw                = False
>>
>>     xyres.xyLineColors           = ["black","red"]
>>
>>     xyres.xyLineThicknesses      = [8,8]
>>
>>     xyres.nglXYFillColors        = ["red","red"]
>>
>>     xyres.nglXYBelowFillColors   = ["red","red"]
>>
>>     xyres.nglXYAboveFillColors   = ["red","red"]
>>
>>
>>
>>     xyline = Ngl.xy(wks,xvar,pter,xyres)
>>
>>
>>
>>     Ngl.overlay(plot,xyline)
>>
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>>
>
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