Drawing streamlines freezes NCL script

From: Samuel Leung <shwl0608_at_nyahnyahspammersnyahnyah>
Date: Thu, 16 Apr 2009 08:59:29 +0800

Hello NCL team,

I faced a problem overlaying streamlines on a map. I used
gsn_csm_streamline to draw the streamlines.

When I ran the ncl for generating the images, the ncl stopped at the
line where gsn_csm_streamline is located, and the postscript file
generated then became bigger and bigger in filesize. This status
seemed not to have an end as I saw the filesize of the postscript file
can reach in giga byte (normally a 10MB postscript is adequate for
making the images I am working on). I needed to terminate the ncl by
myself and no images were obtained.

The scripts I used for the streamline are as follows. It is also in
the end of the ncl.
-----------------------
...
plot = gsn_csm_vector_scalar_map(wks,
uu,vv,rh,res)

resS = True
resS_at_gsnTickMarksOn = False

resS_at_vpWidthF = 0.879
resS_at_vpHeightF = 0.7
resS_at_vpXF = 0.102
resS_at_vpYF = 0.922

resS_at_stMinStepFactorF = 2 ; 2
resS_at_stLengthCheckCount = 4 ; 35
resS_at_stCrossoverCheckCount = -1
resS_at_stMinDistanceF = 0.2
resS_at_stArrowLengthF = 0.01 ; changes the size of the
arrows.
resS_at_stLineThicknessF = 1.5 ; changes the line thickness
resS_at_stMinArrowSpacingF = 0.3

resS_at_stLineColor = "black" ; changes color
resS_at_gsnRightString = ""
resS_at_gsnLeftString = ""
resS_at_gsnCenterString = ""
;resS_at_tfDoNDCOverlay = True

plotS = gsn_csm_streamline(wks,uu,vv,resS)
overlay(plot,plotS)
draw(plot)

frame(wks)

end
-----------------------

I tried to comment the gsn_csm_streamline and the map itself can be
generated successfully. I thought the streamline drawing part is the
root cause of the problem.

This problem can be skipped by setting a larger stMinDistanceF value
but it will result as almost no streamlines drawn.

The ncl version I am using is 4.2.0.a033. I also tried 5.0.0 but it
looked like no difference.

Thanks in advance for your help.

Regards,
Samuel Leung
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Received on Wed Apr 15 2009 - 18:59:29 MDT

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