Some questions regarding optimal alpha value

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

Some questions regarding optimal alpha value

zhanxucong

Dear all,

 

I am new to this library and computational geometry and I am trying to use CGAL for my project. The problem is that I would like to know the shape of a 2D random point clouds boundary on a 2D surface. Thus I tried to get the alpha shape for this point cloud with some alpha value. Intuitively, I tried to used the optimal alpha computed by the following method.

 

Alpha_shape_2 A(points.begin(), points.end(), FT(100000), Alpha_shape_2::REGULARIZED);

A.set_alpha(*A.find_optimal_alpha(1));

 

The result can be seen in the following picture:

 

As can be seen in the picture, it contains many small holes. In order to get rid of these holes, I am thinking to increase the alpha value a little bit. However, that does not guarantee a optimal result in other cases. Therefore, I would like to ask for any suggestions and help to eliminate these small holes. Also I am curious about what the value 1 in the A.set_alpha(*A.find_optimal_alpha(1)) means and how exactly this find_optimal_alphamethod works. Any explanation would be appreciated. Thank you very much!

 

Best regards,

ZHAN, Xucong

Reply | Threaded
Open this post in threaded view
|

Unable to integrate CGAl with other software.

Chaman Singh Verma
Hello All,

CGAL works quite fine if I write standalone programs. However, when I integrate
with other software, I get the following error. I assume that it must be some compiler
ordering issue ( or namespace ). But do not know how to resolve it.

Any help would be great.

csv




/home/csverma/Disk/Software/CompGeom/CGAL/V4.9/include/CGAL/Surface_mesh/IO.h:347:14: error: invalid use of ‘struct boost::property_map<typename CGAL::Surface_mesh<Point_3>::Vertex_index, typename CGAL::Surface_mesh<Point_3>::Point>’
       = mesh.template property_map<typename Mesh::Vertex_index, Point_3>("v:point").first;