[ncl-talk] gsn_csm_streamline_scalar_map segmentation fault

[Alan Brammer]

Would probably help to see the data.   I’ve used this function a lot, with bigger domains than yours and not had issue.  However the function will duplicate domains, so if you’re on a laptop with very limited RAM it may struggle. 

You could save your plotting data to a small netcdf and send it to the list, based on the summary, the netcdf should be small than 1 MB. 

ncout= addfile(“ncl_talk_streamline_data.ncl”,”c”)
ncout->Uwavghist = Uwavghist
ncout->Vwavghist = Vwavghist
ncout->windwavghist = windwavghist


the ftp server is also an option if the output ends up too big.  



Alan




##############################
Alan Brammer,
Post-Doc Researcher

Department of Atmospheric and Environmental Sciences,
University at Albany, State University of New York, Albany, NY, 12222
abrammer at albany.edu
##############################

> On 6 Jul 2017, at 14:05, Meina Wang <mnawang at ucdavis.edu> wrote:
> 
> Dear Mary,
> 
> Thank you very much for your reply, and for running the test case! The variable is not a very large one, and I also tried to do the vector plot using "vcres at vcGlyphStyle = "CurlyVector"" but also got the "Segmentation fault". The only option that works is the vcres at vcGlyphStyle = "WindBarb". Please see below for the printVarSummary info and the resources setting.  Thank you very much again for your help, and please let me know if you spot anything suspicious.
> 
> Output from printVarSummary(Uwavghist):
> Variable: Uwavghist
> Type: float
> Total Size: 76800 bytes
>             19200 values
> Number of Dimensions: 2
> Dimensions and sizes:	[lat | 120] x [lon | 160]
> Coordinates: 
>             lat: [30.0625..44.9375]
>             lon: [-132.9375..-113.0625]
> Number Of Attributes: 1
>   _FillValue :	9.96921e+36
> 
> My resources setting:
>   mpres                       = True
>   mpres at gsnMaximize           = True
>   mpres at mpOutlineOn           = True
>   mpres at mpDataBaseVersion     = "MediumRes"   ; slightly better outlines
>   mpres at mpLandFillColor = "gray91"
> ;---Data is regional
>   mpres at gsnAddCyclic          = False
> ;---Change the streamline levels
>   mpres at stLevelSpacingF       = 30.
>   mpres at stLevelPalette        = "ncl_default" ; "MPL_Spectral"
>   mpres at stLineThicknessF      = 5.0         ; default is 1.0
>   mpres at stLevelSelectionMode  = "ManualLevels"
>   mpres at stMinLevelValF        = 1
>   mpres at stMaxLevelValF        = 15.
>   mpres at stLevelSpacingF       = 1.
>   mpres at mpMinLonF            =  min(lon)               ; select a subregion
>   mpres at mpMaxLonF            =  max(lon)
>   mpres at mpMinLatF            =   min(lat)
>   mpres at mpMaxLatF            =  max(lat)
>   mpres at pmTickMarkDisplayMode = "Always"    ; more detailed tickmarks
> printVarSummary(Uwavghist)
>   plot4 = gsn_csm_vector_scalar_map_ce(wks, Uwavghist,Vwavghist,windwavghist,mpres)
> 
> Best regards,
> Meina
>  
> 
> On Thu, Jul 6, 2017 at 8:58 AM, Mary Haley <haley at ucar.edu <mailto:haley at ucar.edu>> wrote:
> Hi Meina,
> 
> One thing that might cause gsn_csm_streamline_scalar_map to seg fault is if you are trying to plot really large data arrays.
> 
> It's always important to look at your data when NCL isn't plotting it correctly, and we recommend using "printVarSummary" for this.
> 
> How big are U and V? Please insert a "printVarSummary" command and let us know what it reports:
> 
> printVarSummary(U)
> 
> Also, it would help to see how you are calling gsn_csm_streamline_scalar_map, and what resources you're setting.
> 
> I verified that a small test code works just fine, which I've attached here, along with the data file.
> 
> --Mary
> 
> 
> On Wed, Jul 5, 2017 at 6:14 PM, Meina Wang <mnawang at ucdavis.edu <mailto:mnawang at ucdavis.edu>> wrote:
> Dear All,
> 
> I wanted to use the function "gsn_csm_streamline_scalar_map" to plot wind streamline using U and V, with color-coded scaler field sqrt(U^2+V^2), but got "segmentation fault".  I then switched to function "gsn_csm_vector_scalar_map_ce" to do wind barb plot instead using the same data and it worked well.  I have previously used the streamline function and had no problem at all, so I'm wondering if any of you recently ran into the same "segmentation fault" issue as I did.  Is it the internal code of the function crashed?  Thank you.
> 
> P.S. I'm using the NCL version 6.4.0. and ran on Linux machine with gcc (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4
> 
> Best,
> Meina
> 
> -- 
> Meina Wang
> PhD candidate in Atmospheric Science
> Department of Land, Air and Water Resources
> University of California, Davis
> Davis, CA 95616
> 
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> 
> 
> 
> 
> -- 
> Meina Wang
> PhD candidate in Atmospheric Science
> Department of Land, Air and Water Resources
> University of California, Davis
> Davis, CA 95616
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