CGAL users discussion list

["Andi Jochem" <>]

But how can I write the boundaries into a file. I would like to have look on 
the boundaries to be able to decide which is the best alpha for my set of 
points.

andi
-------- Original-Nachricht --------
> Datum: Fri, 08 Aug 2008 15:41:45 +0200
> Von: Mariette Yvinec 
> <>
> An: 
> 
> Betreff: Re: [cgal-discuss] Boundary of alphashapes

> Depending on the value you are going to choose for alpha,
> you can get a whole family of different alphashapes
> with different boundaries.
> 
> I am not sure that one of them corresponds to
> what you are expecting
> 
> 
>  wrote:
> > Hello Mariette,
> > you are right, there is no relation between alphashapes and shapefiles.
> >
> > The only thing I want to do, is to write the boundaries which are
> defined by the set of points into a file.
> >
> > Or am I totally wrong and alphashapes are not the right method to solve
> my problem.
> >
> > Thanks 
> >
> > andi
> >
> >
> > -------- Original-Nachricht --------
> >   
> >> Datum: Fri, 08 Aug 2008 14:59:14 +0200
> >> Von: Mariette Yvinec 
> >> <>
> >> An: 
> >> 
> >> Betreff: Re: [cgal-discuss] Boundary of alphashapes
> >>     
> >
> >   
> >>  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  
> >>
> >>
> >>
> >> -- 
> >> 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  
> 
> 
> 
> -- 
> You are currently subscribed to cgal-discuss.
> To unsubscribe or access the archives, go to
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