Re: How to modify Convex Hull program to give output as Cartesian Coordinates?

*To*: mathgroup at smc.vnet.net*Subject*: [mg48766] Re: [mg48760] How to modify Convex Hull program to give output as Cartesian Coordinates?*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Wed, 16 Jun 2004 04:54:05 -0400 (EDT)*References*: <200406150650.CAA27195@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

On 15 Jun 2004, at 15:50, Gilmar Rodr?guez Pierluissi wrote: > Greetings Mathematica Group!: > > I use the following example, to formulate my question: > > In[1]: data2D = {{4.4, 14}, {6.7, 15.25}, {6.9, 12.8}, {2.1, 11.1}, > {9.5, 14.9},{13.2, 11.9}, {10.3, 12.3}, {6.8, 9.5}, > {3.3, 7.7}, {0.6, 5.1},{5.3, 2.4},{8.45, 4.7}, > {11.5, 9.6},{13.8, 7.3}, {12.9, 3.1}, {11, 1.1}}; > > In[2]: << DiscreteMath`ComputationalGeometry` > > In[3]: convexhull = ConvexHull[data2D] > > Out[3]: {14,6,5,2,1,4,10,11,16,15} > > My question is: > > Is there any way to modify the ConvexHull program to give the > Cartesian coordinates of the points corresponding to the values > 14,6,5,2,1,4,10,11,16,15; instead of Out[3] above? > > Thank you! > > Yes. convexhull = data2D[[ConvexHull[data2D]]] {{13.8, 7.3}, {13.2, 11.9}, {9.5, 14.9}, {6.7, 15.25}, {4.4, 14}, {2.1, 11.1}, {0.6, 5.1}, {5.3, 2.4}, {11, 1.1}, {12.9, 3.1}} Andrzej Kozlowski Chiba, Japan http://www.mimuw.edu.pl/~akoz/

**References**:**How to modify Convex Hull program to give output as Cartesian Coordinates?***From:*gilmar.rodriguez@nwfwmd.state.fl.us (Gilmar Rodr?guez Pierluissi)