CGAL 5.6.1  2D Triangulations on the Sphere

#include <CGAL/Triangulation_on_sphere_vertex_base_2.h>
Vb.
The class Triangulation_on_sphere_vertex_base_2
is the default model for the concept TriangulationOnSphereVertexBase_2
and the default vertex base class for triangulations on the sphere.
Triangulation_on_sphere_vertex_base_2
can be simply plugged into the triangulation data structure of a triangulation, or used as a base class to derive other base vertex classes tuned for specific applications.
Traits  must be a geometric traits class which provides the type Point_on_sphere_2 . It is strongly recommended to instantiate this traits class with the model used for the triangulation traits class. This ensures that the point type defined by Triangulation_on_sphere_vertex_base_2 is the same as the point type defined by the triangulation. 
Vb  must be a model of the concept TriangulationDSVertexBase_2 . By default this parameter is instantiated by Triangulation_ds_vertex_base_2<> . 
CGAL::Triangulation_ds_vertex_base_2<Tds>
CGAL::Triangulation_on_sphere_face_base_2<Traits,Fb>
CGAL::Triangulation_vertex_base_with_info_2<Info,Traits,Vb>
CGAL::Triangulation_on_sphere_2<Traits,Tds>
Types  
typedef Traits::Point_on_sphere_2  Point 