CGAL users discussion list

Thank you Bjoern,
you are right.

Andi
> -------- Original-Nachricht --------
> Datum: Fri, 08 Aug 2008 15:04:57 +0200
> Von: "Björn Zehner" 
> <>
> An: 
> 
> Betreff: Re: [cgal-discuss] Boundary of alphashapes
> 
> Hello,
> I hope I do not miss completely the point, but I think he wants the
> polygon 
> that describes the outer (possibly concave) boundary of the alpha shape.
> Am 
> I right Andi?
> Kind regards,
> Bjoern Zehner
>  
> 
> ----- Ursprüngliche Nachricht -----
> Von: Mariette Yvinec 
> <>
> Datum: Freitag, 8. August 2008, 14:59
> Betreff: Re: [cgal-discuss] Boundary of alphashapes
> An: 
> 
> 
> 
> 
> > From what I see in wikipedia
> > there is no relationship between alphashapes and shape file...
> 
> > and I still don't get what shape you want to get
> 
> > Andi Jochem wrote: 
> > > Hello Mariette,  >   > a shapefile is a popular geospatial vector data
> > format for geographic information systems  > 
> > (http://en.wikipedia.org/wiki/Shapefile)  >   > As you already know, I
> am 
> > not very familiar with alphashapes, but maybe you can help me.  >   >  
> > 
> >   > I am just looking for a method to get the shape, defined by a set of
> > points (the "concave hull" , not the convex hull). After an intensiv 
> > google search, I found the CGAL library, installed it and tried to write
> > a function using alpha_shapes_3.  >   > My question is: How can I get, 
> > the shape which is defined by a set of points in file?  >    >   >
> Thanks 
> >  >   > Andi  >   >   >   >   > -------- Original-Nachricht --------  >  
> > > > Datum: Fri, 08 Aug 2008 14:37:54 +0200  > Von: Mariette Yvinec 
> > > <>
> > >   > An: 
> > > 
> > >   > Betreff: Re: [cgal-discuss]
> Boundary 
> > > of alphashapes  >     
> > >   >   
> > > > I am rather familiar with Alpha_shape_3  > but I  can't answer your 
> > > questions  > because I do not  understand them...  > In particular I 
> > > don't know  > - what is a shapefile  > - nor which polygon you want to
> > > get out of alpha_shapes_3  > - nor what is  a roof plane  >   > 
> > > 
> > >  wrote:  >     
> > > > > Hello,  > I wrote a function to get the alphashapes of a set of 
> > > > points, but how  >       
> > > > can I  >     
> > > > > transform this alphashapes in a polygon...???  > Is it posssible
> to 
> > > > transform the created alphashape in a shapefile???  >   > Is anybody
> > > > familiar with alphashapes??   >   > Thanks a lot.  >   > andi  >    
> > > > >       
> > > > --   > Mariette Yvinec  > Geometrica project team  > INRIA  
> > > Sophia-Antipolis    >   >   >   > --   > You are currently subscribed 
> > > to cgal-discuss.  > To unsubscribe or access the archives, go to  > 
> > > https://lists-sop.inria.fr/wws/info/cgal-discuss  >     
> > >   >   
> 
> > --   > Mariette Yvinec  > Geometrica project team  > INRIA  
> Sophia-Antipolis    >   >   >  
> 
> 
> ------------------------------------------------------------------------- 
> Dr. Bjoern Zehner 
> UFZ Centre for Environmental Research Leipzig-Halle 
> Permoserstrasse 15 
> 04318 Leipzig 
> Germany 
> http://www.ufz.de/index.php?en=5673 
> Tel: ++49 (341) 235 3979 
> Fax: ++49 (341) 235 3939
> 

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