geometry/core/topological_dimension.hpp

0001 // Boost.Geometry (aka GGL, Generic Geometry Library)
0002
0003 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
0004 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
0005 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
0006
0007 // This file was modified by Oracle on 2020-2022.
0008 // Modifications copyright (c) 2020-2022, Oracle and/or its affiliates.
0009 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0010
0011 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
0012 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
0013
0014 // Use, modification and distribution is subject to the Boost Software License,
0015 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0016 // http://www.boost.org/LICENSE_1_0.txt)
0017
0018
0019 #ifndef BOOST_GEOMETRY_CORE_TOPOLOGICAL_DIMENSION_HPP
0020 #define BOOST_GEOMETRY_CORE_TOPOLOGICAL_DIMENSION_HPP
0021
0022
0023 #include <type_traits>
0024
0025 #include <boost/geometry/core/tag.hpp>
0026 #include <boost/geometry/core/tags.hpp>
0027
0028
0029 namespace boost { namespace geometry
0030 {
0031
0032
0033 #ifndef DOXYGEN_NO_DISPATCH
0034 namespace core_dispatch
0035 {
0036
0037
0038 template <typename GeometryTag>
0039 struct top_dim {};
0040
0041
0042 template <>
0043 struct top_dim<point_tag>      : std::integral_constant<int, 0> {};
0044
0045
0046 template <>
0047 struct top_dim<linestring_tag> : std::integral_constant<int, 1> {};
0048
0049
0050 template <>
0051 struct top_dim<segment_tag>    : std::integral_constant<int, 1> {};
0052
0053
0054 // ring: topological dimension of two, but some people say: 1 !!
0055 // NOTE: This is not OGC LinearRing!
0056 template <>
0057 struct top_dim<ring_tag>       : std::integral_constant<int, 2> {};
0058
0059
0060 // TODO: This is wrong! Boxes may have various topological dimensions
0061 template <>
0062 struct top_dim<box_tag>        : std::integral_constant<int, 2> {};
0063
0064
0065 template <>
0066 struct top_dim<polygon_tag>    : std::integral_constant<int, 2> {};
0067
0068
0069 template <>
0070 struct top_dim<multi_point_tag> : std::integral_constant<int, 0> {};
0071
0072
0073 template <>
0074 struct top_dim<multi_linestring_tag> : std::integral_constant<int, 1> {};
0075
0076
0077 template <>
0078 struct top_dim<multi_polygon_tag> : std::integral_constant<int, 2> {};
0079
0080
0081 template <>
0082 struct top_dim<geometry_collection_tag> : std::integral_constant<int, -1> {};
0083
0084
0085 } // namespace core_dispatch
0086 #endif
0087
0088
0089
0090
0091
0092 /*!
0093     \brief Meta-function returning the topological dimension of a geometry
0094     \details The topological dimension defines a point as 0-dimensional,
0095         a linestring as 1-dimensional,
0096         and a ring or polygon as 2-dimensional.
0097     \see http://www.math.okstate.edu/mathdept/dynamics/lecnotes/node36.html
0098     \ingroup core
0099 */
0100 template <typename Geometry>
0101 struct topological_dimension
0102     : core_dispatch::top_dim<typename tag<Geometry>::type> {};
0103
0104
0105 }} // namespace boost::geometry
0106
0107
0108 #endif // BOOST_GEOMETRY_CORE_TOPOLOGICAL_DIMENSION_HPP