# Filling colors in Delaunay triangles

From: Roshil Paudyal <p.roshil1994_at_nyahnyahspammersnyahnyah>
Date: Sun Jul 07 2013 - 11:31:02 MDT

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)

begin

NARC = 50

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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Received on Sun Jul 7 11:31:14 2013

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