Re: Filling colors in Delaunay triangles

Hi Roshi,
I will be looking at your script and output as soon as possible.
 -dave

 
On Jul 8, 2013, at 12:34 PM, Adam Phillips <asphilli@ucar.edu> wrote:

> Hi Roshil,
> This is a rather complicated issue. First off, you are setting gsFillColor = False, when you should be setting it to a color index or color name.
> See: http://www.ncl.ucar.edu/Document/Graphics/Resources/gs.shtml#gsFillColor
>
> Second, according to a search I did on the NCL web page, it's better to have your input longitude coordinates to be in the 0:360 range, EXCEPT when your coordinates cross the prime meridian where they should range from -180:180. You will see where statement coding in the attached script to account for this.
>
> Third, there are two triangles that you are trying to draw that are rather large. Here are their coordinates:
> (0) (40.719,245.982) (45.591,237.4) (-37.733,145.4) (40.719,245.982)
> (0) (40.719,245.982) (-37.733,145.4) (-13.533,288.067) (40.719,245.982)
>
> These 2 triangles are large enough that they are causing NCL to color fill outside the triangles instead of inside. I am not sure how to get NCL to fill inside those two triangles as opposed to outside. Someone else will need to answer that.
>
> Finally, I used gsn_add_polygon due to personal preference. In this case it automatically switched the drawing of the continental outlines to be drawn last, which I assume you prefer.
>
> I have attached a script and the example graphic.
> Good luck,
> Adam
>
> On 7/8/13 9:38 AM, Roshil Paudyal wrote:
>> Hi,
>>
>> Thank you for your reply.
>> I tried that but it still doesn't solve the problem. Using polyline gives good results; so I don't think there is anything wrong in the rest of the code. The problem must lie somewhere in executing the gsn_polygon function.
>>
>> It would be great if you could run this script once, which may make the problem clearer. It does give some output; but that is very different from what is expected (or what polyline gives). I have already attached the only datafile I used (illdt1).
>>
>> Thank you,
>> Roshil
>>
>> On Mon, Jul 8, 2013 at 10:38 AM, Adam Phillips <asphilli@ucar.edu> wrote:
>> Hi Roshil,
>> I believe you have to enclose a complete polygon for gsn_polygon to work. In other words, the first and last latitude/longitude points are usually the same. Also, you need to make sure that you are advancing the frame at the end of your script.
>>
>> Try changing this:
>>
>> qlat = new(3,float)
>> qlon = new(3,float)
>> gsres@gsEdgesOn = True
>> gsres@gsEdgeColor = 4
>> gsres@gsFillColor = False
>> do np=0,num_triangles-1
>> qlat(0) = lat_in(triangles(np,0))
>> qlon(0) = lon_in(triangles(np,0))
>> qlat(1) = lat_in(triangles(np,1))
>> qlon(1) = lon_in(triangles(np,1))
>> qlat(2) = lat_in(triangles(np,2))
>> qlon(2) = lon_in(triangles(np,2))
>> gsn_polygon(wks,map,qlon,qlat,gsres)
>> end do
>>
>> to this:
>>
>> qlat = new(4,float)
>> qlon = new(4,float)
>> gsres@gsEdgesOn = True
>> gsres@gsEdgeColor = 4
>> gsres@gsFillColor = False
>> do np=0,num_triangles-1
>> qlat(0) = lat_in(triangles(np,0))
>> qlon(0) = lon_in(triangles(np,0))
>> qlat(1) = lat_in(triangles(np,1))
>> qlon(1) = lon_in(triangles(np,1))
>> qlat(2) = lat_in(triangles(np,2))
>> qlon(2) = lon_in(triangles(np,2))
>> qlat(3) = qlat(0)
>> qlon(3) = qlon(0)
>> gsn_polygon(wks,map,qlon,qlat,gsres)
>> end do
>> frame(wks)
>>
>>
>> If that does not solve the problem, please respond to ncl-talk to let everyone know.
>> Adam
>>
>>
>> On 07/07/2013 11:31 AM, Roshil Paudyal wrote:
>>> Hi,
>>>
>>> I am trying to plot some data on a sphere and create a Delaunay triangulation out of it and fill colors into each of the triangles using a custom color map. Following code does a good job of creating the triangulation: (ncl v. 6.1.2 in cygwin)
>>>
>>>
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>>>
>>> begin
>>>
>>> NARC = 50
>>>
>>> jps = asciiread("illdt1.txt",(/101,4/),"float")
>>> id_in = jps(1:100,0)
>>> lat_in = jps(1:100,1)
>>> lon_in = jps(1:100,2)
>>> dt_in = jps(1:100,3)
>>> N = 100
>>>
>>>
>>> gsres = True
>>>
>>>
>>> ; Create the triangulation.
>>> ;
>>> triangles = csstri(lat_in,lon_in)
>>> tri_sizes = dimsizes(triangles)
>>> num_triangles = tri_sizes(0)
>>>
>>>
>>>
>>> cmap = (/ \
>>> (/ 1., 1., 1. /), \
>>> (/ 0., 0., 0. /), \
>>> (/ 1., 0., 0. /), \
>>> (/ 0., 0., 1. /), \
>>> (/ 1., 0., 0. /), \
>>> (/ 0., 1., 0. /), \
>>> (/ 0., .8, 0. /), \
>>> (/ .65, .65, .65 /) \
>>> /)
>>>
>>> NCGM=1
>>> X11=0
>>> PS=0
>>> PDF=0
>>>
>>> if (NCGM .eq. 1) then
>>> wks = gsn_open_wks("ncgm","nm21n")
>>> end if
>>> if (X11 .eq. 1) then
>>> wks = gsn_open_wks("x11","nm21n")
>>> end if
>>> if (PS .eq. 1) then
>>> wks = gsn_open_wks("ps","nm21n")
>>> end if
>>> if (PDF .eq. 1) then
>>> wks = gsn_open_wks("pdf","nm21n")
>>> end if
>>> gsn_define_colormap(wks,cmap)
>>>
>>>
>>>
>>> ;
>>> ; Draw a globe
>>> ;
>>> map_resources = True
>>> map_resources@gsnFrame = False
>>> map_resources@mpOutlineBoundarySets = "National"
>>> map_resources@mpNationalLineColor = 1
>>> map_resources@mpGeophysicalLineColor = 7
>>>
>>> map_resources@mpLimbLineColor = 7
>>> map_resources@mpGridLineColor = 0
>>> map_resources@mpGridAndLimbDrawOrder = "PreDraw"
>>>
>>> map_resources@mpCenterLatF = 40.
>>> map_resources@mpCenterLonF = -105.
>>> map_resources@vpXF = 0.06
>>> map_resources@vpYF = 0.90
>>> map_resources@vpWidthF = 0.88
>>> map_resources@vpHeightF = 0.88
>>> map_resources@mpSatelliteDistF = 4.0
>>>
>>> map_resources@mpGreatCircleLinesOn = True
>>>
>>> map = gsn_map(wks,"Satellite",map_resources)
>>>
>>>
>>>
>>> ; Draw the triangles.
>>> ;Ignore the blue for now
>>>
>>> qlat = new(4,float)
>>> qlon = new(4,float)
>>> gsres@gsLineColor = 5
>>> do np=0,num_triangles-1
>>> qlat(0) = lat_in(triangles(np,0))
>>> qlon(0) = lon_in(triangles(np,0))
>>> qlat(1) = lat_in(triangles(np,1))
>>> qlon(1) = lon_in(triangles(np,1))
>>> qlat(2) = lat_in(triangles(np,2))
>>> qlon(2) = lon_in(triangles(np,2))
>>> qlat(3) = lat_in(triangles(np,0))
>>> qlon(3) = lon_in(triangles(np,0))
>>> gsn_polyline(wks,map,qlon,qlat,gsres)
>>> end do
>>>
>>> end
>>>
>>> However, is there a way to fill colors into the triangles created using polylines? I didn't find any. So, I thought maybe I could give the end points of triangles as an input to gsn_polygon. If that created the triangles, that would have given me a full set of resources to modify, including the fill colors. So, I replaced the blue part with the following code:
>>>
>>> qlat = new(3,float)
>>> qlon = new(3,float)
>>> gsres@gsEdgesOn = True
>>> gsres@gsEdgeColor = 4
>>> gsres@gsFillColor = False
>>> do np=0,num_triangles-1
>>> qlat(0) = lat_in(triangles(np,0))
>>> qlon(0) = lon_in(triangles(np,0))
>>> qlat(1) = lat_in(triangles(np,1))
>>> qlon(1) = lon_in(triangles(np,1))
>>> qlat(2) = lat_in(triangles(np,2))
>>> qlon(2) = lon_in(triangles(np,2))
>>> gsn_polygon(wks,map,qlon,qlat,gsres)
>>> end do
>>>
>>> But this doesn't even create all the triangles. So, is there a way to fix this problem? I have attached the data I used for this (illdt1.txt).
>>>
>>>
>>> Thank you,
>>> Roshil
>>>
>>>
>>>
>>>
>>> _______________________________________________
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>>
>> --
>> ______________________________________________________________
>> Adam Phillips asphilli@ucar.edu
>> NCAR/Climate and Global Dynamics Division (303) 497-1726
>> P.O. Box 3000
>> Boulder, CO 80307-3000 http://www.cgd.ucar.edu/cas/asphilli
>>
>
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Received on Tue Jul 9 13:21:48 2013