[ncl-talk] Trying to draw circles with different radius in Km around a station

[Karin Meier-Fleischer]

Hi Soumik,

you can use polymarkers to plot the circles around lat/lon locations. 
Have a look at example newcolor_4.ncl at 
http://ncl.ucar.edu/Applications/Scripts/newcolor_4.ncl

I've attached an example script using random data for marker size and 
lat/lon locations overlayed on filled contour map.

Hope this helps.

-Karin

Am 08.02.18 um 00:55 schrieb Soumik Basu:
> Hello NCL-users,
>
> I am trying to draw circles around a station with different radius. 
> For example 50 Km, 100 Km, 150 Km etc.
>
> So, I am wondering if there is any way to do it in NCL.
>
> I looked at the "nggcog" function but from the description what I 
> understand is that it can draw circles along a great circle only not 
> according to a given distance.
>
> Thank you for any help.
>
> Thanks,
> Soumik
>
> -- 
> -- 
> “We’ve all got both light and dark inside us. What matters is the part 
> we choose to act on. That’s who we really are.” – J.K. Rowling
>
> **************************************************************************************************
> Dr. Soumik Basu
> Post Doctoral Research Faculty
> International Arctic Research Center, UAF, Fairbanks, AK, USA
> PhD in Atmospheric Sciences
> M.Sc. in Atmospheric Sciences
> Email: suvro05 at gmail.com <mailto:suvro05 at gmail.com>
> website: http://soumikbasu.weebly.com/
>
> ***************************************************************************************************
>
>
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begin

  f = addfile("$HOME/NCL/NUG/Version_1.0/data/rectilinear_grid_2D.nc","r")

  var = f->tsurf(0,:,:)
  
  sizes  = ispan(25,65,5)/1000.
  colors = (/"gray10","gray20","gray30","gray40","gray50","gray60","gray70","gray80","gray90"/)
  nmarker    = dimsizes(sizes)
  
  marker_lat = random_uniform( -80, 80,nmarker)
  marker_lon = random_uniform(-150,150,nmarker)
  
  wks = gsn_open_wks("png","plot_marker_on_contours")

  res                      =  True
  res at gsnMaximize          =  True
  res at gsnDraw              =  False
  res at gsnFrame             =  False
         
  res at cnFillOn             =  True
  res at cnLinesOn            =  False
  res at cnLineLabelsOn       =  False
  
  res at mpFillOn             =  False
;  res at mpFillDrawOrder      = "PreDraw"
;  res at mpOutlineDrawOrder   = "PostDraw"
  
  plot = gsn_csm_contour_map(wks,var,res)
  
  mkres                    =  True
  mkres at gsMarkerThicknessF =  2.0           ; Twice as thick
  mkres at gsMarkerIndex      =  16            ; Filled dots
  mkres at gsMarkerOpacityF   =  0.85
      
  do i = 0,nmarker -1
     mkres at gsMarkerSizeF   =  sizes(i)
     mkres at gsMarkerColor   =  colors(i)
;     mkres at tfPolyDrawOrder = "PostDraw"                      ; default is "PostDraw"  
       
     mks = unique_string("mks")
     plot@$mks$ = gsn_add_polymarker(wks,plot,marker_lon(i),marker_lat(i),mkres)
  end do
  
  draw(plot)
  frame(wks)
  
end