RE: Convex Hull

• To: mathgroup at smc.vnet.net
• Subject: [mg20866] RE: [mg20839] Convex Hull
• From: "Ersek, Ted R" <ErsekTR at navair.navy.mil>
• Date: Thu, 18 Nov 1999 01:09:42 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

```Virgil Stokes  wrote:
-------------------------------
I have two ellipses that in general are different (lengths of minor/major
axes may differ) and are positioned at random in the XY-plane with the
condition that they do not overlap or touch at any point along their
boundaries.

The problem is to find the convex hull for these two ellipses -- fast. Any
since I am still unable to get messages generated from the MathGroup list.
-------------------

I suppose the ellipses are represented as lists of points inside Line. If
not you could use ParametricPlot to make the lists of points. You could then
use the convex hull algorithm at:
http://www.mathsource.com/Content/Applications/Graphics/2D/0209-854

I don't know if this algorithm can find the convex hull of multiple
polygons. If that's a problem you could find a way to connect the polygons
into one polygon. I doubt this will run lightning fast, but I don't know how
you can do much better.

--------------------
Regards,
Ted Ersek

For Mathematica tips, tricks see
http://www.dot.net.au/~elisha/ersek/Tricks.html

```

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