| [Q] PLOTS/POLYFILL clipping in map [message #6654] |
Thu, 01 August 1996 00:00 |
Iarla Kilbane-Dawe
Messages: 7
Registered: May 1995
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Junior Member |
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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.
____________________________________________________________ _________
Iarla Kilbane-Dawe Email: iarla@atm.ch.cam.ac.uk
Centre for Atmospheric Science Phone: ++44 (01223) 336524
Cambridge University Fax: ++44 (01223) 336473
____________________________________________________________ _________
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| 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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