Question

我正在创建一个包装器，允许使用带有Boost.Geometry的OGR类。到目前为止，我已经创建了必要的迭代器外观，并使用Boost.Geometry注册了OGR的几何类（OGRPoint，OGRLineString，OGRLinearRing和OGRPolygon）。

现在，我想使用带有boost的OGRGeometry::Distance()等OGR类谓词而不是Boost.Geometry使用的谓词（因为，例如，股票Boost.Geometry 1.57.0没有任何概念地图投影）。它适用于boost::geometry::distance(OGRPoint, OGRPoint)，但不适用于bg::distance(OGRPoint, OGRLineString)或任何其他积分。我的猜测是因为Boost.Geometry将线串，环和多边形视为迭代的有序点集合，因为编译器试图实例化以下模板：

struct boost::geometry::strategy::distance::services::default_strategy<
        boost::geometry::point_tag,
        boost::geometry::segment_tag,
        OGRPoint,                           // NOTE: Twice OGRPoint!
        OGRPoint,
        MyCode::OGRCoordinateSystemTag,
        MyCode::OGRCoordinateSystemTag, void>

完整的错误消息如下：

In file included from /usr/include/boost/geometry/strategies/strategies.hpp:30:0,
                 from /usr/include/boost/geometry/geometry.hpp:43,
                 from /usr/include/boost/geometry.hpp:17,
                 from ../../../winzent/test/simulation/OGRLineStringAdapterTest.cpp:7:
/usr/include/boost/geometry/strategies/distance.hpp: In instantiation of 'struct boost::geometry::strategy::distance::services::default_strategy<boost::geometry::point_tag, boost::geometry::segment_tag, OGRPoint, OGRPoint, Winzent::Simulation::boost::OGRCoordinateSystemTag, Winzent::Simulation::boost::OGRCoordinateSystemTag, void>':
/usr/include/boost/geometry/algorithms/detail/distance/default_strategies.hpp:57:8:   required from 'struct boost::geometry::detail::distance::default_strategy<OGRPoint, OGRLineString, boost::geometry::pointlike_tag, boost::geometry::linestring_tag, false>'
/usr/include/boost/geometry/algorithms/detail/distance/default_strategies.hpp:73:8:   required from 'struct boost::geometry::detail::distance::default_strategy<OGRLineString, OGRPoint, boost::geometry::linestring_tag, boost::geometry::pointlike_tag, true>'
/usr/include/boost/geometry/strategies/distance_result.hpp:60:8:   required from 'struct boost::geometry::resolve_strategy::distance_result<OGRLineString, OGRPoint, boost::geometry::default_strategy>'
/usr/include/boost/geometry/strategies/distance_result.hpp:79:8:   required from 'struct boost::geometry::resolve_variant::distance_result<OGRLineString, OGRPoint, boost::geometry::default_strategy>'
/usr/include/boost/geometry/strategies/distance_result.hpp:199:8:   required from 'struct boost::geometry::distance_result<OGRLineString, OGRPoint, boost::geometry::default_strategy>'
/usr/include/boost/geometry/strategies/distance_result.hpp:205:8:   required from 'struct boost::geometry::distance_result<OGRLineString, OGRPoint, void>'
/usr/include/boost/geometry/strategies/default_distance_result.hpp:35:8:   required from 'struct boost::geometry::default_distance_result<OGRLineString, OGRPoint>'
/usr/include/boost/geometry/algorithms/detail/distance/interface.hpp:392:1:   required by substitution of 'template<class Geometry1, class Geometry2> typename boost::geometry::default_distance_result<Geometry1, Geometry2>::type boost::geometry::distance(const Geometry1&, const Geometry2&) [with Geometry1 = OGRLineString; Geometry2 = OGRPoint]'
../../../winzent/test/simulation/OGRLineStringAdapterTest.cpp:71:62:   required from here
/usr/include/boost/geometry/strategies/distance.hpp:97:456: error: no matching function for call to 'assertion_failed(mpl_::failed************ (boost::geometry::strategy::distance::services::default_strategy<boost::geometry::point_tag, boost::geometry::segment_tag, OGRPoint, OGRPoint, Winzent::Simulation::boost::OGRCoordinateSystemTag, Winzent::Simulation::boost::OGRCoordinateSystemTag, void>::NOT_IMPLEMENTED_FOR_THIS_POINT_TYPE_COMBINATION::************)(mpl_::assert_::types<OGRPoint, OGRPoint, Winzent::Simulation::boost::OGRCoordinateSystemTag, Winzent::Simulation::boost::OGRCoordinateSystemTag>))'
     BOOST_MPL_ASSERT_MSG

所以我尝试专门为struct boost::geometry::detail::distance::default_strategy<OGRPoint, OGRLineString, boost::geometry::pointlike_tag, boost::geometry::linestring_tag, false>提供模板专门化，但没有运气---相同的错误信息占优势。

这是我的代码：

namespace boost {
    namespace geometry {
        namespace detail {
            namespace distance {


                template <>
                struct default_strategy<
                        OGRPoint,
                        OGRLineString,
                        pointlike_tag,
                        linestring_tag,
                        false>
                {
                    typedef OGRPointToLineStringDistanceStrategy type;
                };
            } // namespace distance
        } // namespace detail
    } // namespace geometry
} // namespace boost

如何“拦截”导致使用迭代器/范围概念的模板实例并直接使用OGRGeometry::Distance()？

Answer 1

事实证明，问题与使用两种不同算法的OGR和Boost无关。相反，这是我的适配器代码应该责备。更具体地说，我编写的迭代器外观是为了使OGRLineString，OGRLinearRing和最终OGRPolygon适应Boost.Geometry代码。我在发现问题后立即发布了一个问题：Create a well-behaved iterator for a write-to-pointer API。

我目前工作的（和最终版）版本以a GitHub project的形式提供。也许有人觉得它很有用。

如何为OGRPoint和OGRLineString注册Boost.Geometry距离策略？

1 个答案: