1 // Boost.Geometry (aka GGL, Generic Geometry Library)
2 
3 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
4 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
5 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
6 
7 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
8 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
9 
10 // Use, modification and distribution is subject to the Boost Software License,
11 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
12 // http://www.boost.org/LICENSE_1_0.txt)
13 
14 
15 #ifndef BOOST_GEOMETRY_CORE_TOPOLOGICAL_DIMENSION_HPP
16 #define BOOST_GEOMETRY_CORE_TOPOLOGICAL_DIMENSION_HPP
17 
18 
19 #include <boost/mpl/int.hpp>
20 
21 
22 #include <boost/geometry/core/tag.hpp>
23 #include <boost/geometry/core/tags.hpp>
24 
25 
26 namespace boost { namespace geometry
27 {
28 
29 
30 #ifndef DOXYGEN_NO_DISPATCH
31 namespace core_dispatch
32 {
33 
34 
35 template <typename GeometryTag>
36 struct top_dim {};
37 
38 
39 template <>
40 struct top_dim<point_tag>      : boost::mpl::int_<0> {};
41 
42 
43 template <>
44 struct top_dim<linestring_tag> : boost::mpl::int_<1> {};
45 
46 
47 template <>
48 struct top_dim<segment_tag>    : boost::mpl::int_<1> {};
49 
50 
51 // ring: topological dimension of two, but some people say: 1 !!
52 // NOTE: This is not OGC LinearRing!
53 template <>
54 struct top_dim<ring_tag>       : boost::mpl::int_<2> {};
55 
56 
57 // TODO: This is wrong! Boxes may have various topological dimensions
58 template <>
59 struct top_dim<box_tag>        : boost::mpl::int_<2> {};
60 
61 
62 template <>
63 struct top_dim<polygon_tag>    : boost::mpl::int_<2> {};
64 
65 
66 template <>
67 struct top_dim<multi_point_tag> : boost::mpl::int_<0> {};
68 
69 
70 template <>
71 struct top_dim<multi_linestring_tag> : boost::mpl::int_<1> {};
72 
73 
74 template <>
75 struct top_dim<multi_polygon_tag> : boost::mpl::int_<2> {};
76 
77 
78 } // namespace core_dispatch
79 #endif
80 
81 
82 
83 
84 
85 /*!
86     \brief Meta-function returning the topological dimension of a geometry
87     \details The topological dimension defines a point as 0-dimensional,
88         a linestring as 1-dimensional,
89         and a ring or polygon as 2-dimensional.
90     \see http://www.math.okstate.edu/mathdept/dynamics/lecnotes/node36.html
91     \ingroup core
92 */
93 template <typename Geometry>
94 struct topological_dimension
95     : core_dispatch::top_dim<typename tag<Geometry>::type> {};
96 
97 
98 }} // namespace boost::geometry
99 
100 
101 #endif // BOOST_GEOMETRY_CORE_TOPOLOGICAL_DIMENSION_HPP
102