Re: unknown diagonal white line on gsn_csm_map plot

Hmmm…I believe you, but that's counter to what I was about to report. What color did you set the resource to, and which workstation device are you using (always png?)?

For my part, what I've observed is that whenever the map background is completely solid (i.e., solid landmass or solid ocean, etc.) the line appears. If there's a sliver of ocean present against a landmass, or the presence of islands in a plot of predominantly ocean, the line does not appear. I've been reliably able to produce and predict when/if it will occur, and for me it happens whether or not mpLandFillColor is set (in fact, I set it to a dark color to emphasize the diagonal when its present). It also happens regardless of workstation type.

All this and some other experiments suggests to me its an artifact of our graphics subsystem, the nature and origin of which I don't understand at the moment. Thus I don't really have a work-around to offer, other than the line seems to be less visible (but not invisible) for the older postscript/pdf formats (device names "oldps", "oldpdf" with ncl 6.1.0, or just "ps", "pdf" with 6.0.0)

I'm going to file a ticket on this one…

Rick

 
On Dec 18, 2012, at 3:01 PM, Ronny Berndt <ronny.berndt@uni-jena.de> wrote:

> Hi,
>
> it seems that if you set the resource @mpLandFillColor the white line is gone.
> Is @mpLandFillColor unset, the white line comes again...
>
> Ronny
>
> Am 18.12.2012 um 21:57 schrieb Rick Brownrigg:
>
>> That's interesting -- it shows up in every output format we support. I don't know why at the moment, but am checking in to it…
>>
>> Rick
>>
>> On Dec 18, 2012, at 12:43 PM, Ronny Berndt <ronny.berndt@uni-jena.de> wrote:
>>
>>> Hi,
>>>
>>> why is there a diagonal white line from the lower left corner to upper right?
>>> How can I prevent this?
>>>
>>> ncl-script:
>>>
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>>>
>>> begin
>>>
>>> wks_type = "png"
>>> wks_name = "latlines"
>>> wks = gsn_open_wks(wks_type, wks_name) ; Open a workstation.
>>>
>>> res = True
>>> res@gsnFrame = False ; Don't draw or advance
>>> res@gsnDraw = False ; frame yet.
>>> res@gsnMaximize = True
>>>
>>>
>>> ;---This will be our base, so make it a map plot.
>>> ;res@tfDoNDCOverlay = False
>>> ;res@gsnAddCyclic = False
>>> res@mpProjection = "CylindricalEquidistant" ; Projection
>>> res@mpOutlineOn = True
>>> res@mpDataBaseVersion = "MediumRes"
>>> res@mpOutlineBoundarySets = "AllBoundaries"
>>> ;res@mpOutlineBoundarySets = "National" ; country borders
>>> res@mpNationalLineThicknessF = 2.0
>>> res@mpLimitMode ="LatLon"
>>> res@mpMinLatF = -21.87
>>> res@mpMaxLatF = -11.09
>>> res@mpMinLonF = 14.21
>>> res@mpMaxLonF = 25.87
>>>
>>> Map = gsn_csm_map(wks, res)
>>>
>>> pres = True ; polyline mods desired
>>> pres@gsLineThicknessF = 2.0 ; line thickness
>>> pres@gsLineColor = "blue" ; color of lines
>>>
>>> val = gsn_add_polyline(wks,Map,(/14.21,25.87/),(/-12.63,-12.63/),pres)
>>>
>>> draw(Map)
>>> frame(wks)
>>>
>>> ;delete(res)
>>>
>>> ;make high density png with imagemagick
>>> ;delete(wks)
>>>
>>> options = "mogrify -strip -trim -geometry 1000x1000 -density 300 -units pixelsperinch " + wks_name + ".png"
>>> ;system(options)
>>>
>>> end
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>>
>

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Received on Tue Dec 18 15:26:19 2012