| Re: [Q] PLOTS/POLYFILL clipping in map [message #6748 is a reply to message #6654] |
Thu, 01 August 1996 00:00  |
Robert.M.Candey
Messages: 23
Registered: June 1995
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Junior Member |
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In article
<Pine.SOL.3.91.960801125009.23811K-100000@Cacofonix.atm.ch.cam.ac.uk>,
Iarla Kilbane-Dawe <iarla@atm.ch.cam.ac.uk> wrote:
> Hello,
>
> does anyone have any experience of using the clip keyword with
> plot and polyfill when a map projection is in use which has been
> restricted using the limits keyword? We don't seem to be able to get
> things to plot inside the chosen region if any of the vector lies outside
> it. Equally, we haven't been able to get the routines to clip filled
> polygons at the edge of the region.
>
> Does anyone have any advice please?
>
> Many thanks in advance.
>
> Iarla.
I haven't found the clip keyword to work either, I think since the edge of
a polygon that goes over the side of the plot on one side is often still
in bounds on the other side. I use the following to check each polygon
(in this case using triangles returned from triangulate) and not plot if
the polygon is large in normalized coordinates:
pAll = convert_coord(Lon, Lat, /data, /to_normal)
pLon = pAll(0,*) & pLat = pAll(1,*)
for i=0L,n_elements(triangles(0,*))-1 do begin
tri1 = triangles(*,i)
Lon3 = Lon(tri1) & Lat3 = Lat(tri1)
Zb1 = Zb(tri1(0))
if (total(abs(pLon(tri1)-shift(pLon(tri1),1))) lt 0.1) and $
(total(abs(pLat(tri1)-shift(pLat(tri1),1))) lt 0.1) then $
polyfill, Lon3, Lat3, color=Zb1(0), noclip=0
endfor
This is for full polar plots and may not be the solution for restricted regions.
--
Robert.M.Candey@gsfc.nasa.gov
NASA Goddard Space Flight Center, Code 632
Greenbelt, MD 20771 USA 1-301-286-6707
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