[Boost-commit] svn:boost r72208 - trunk/boost/geometry/strategies/spherical

Subject: [Boost-commit] svn:boost r72208 - trunk/boost/geometry/strategies/spherical
From: barend.gehrels_at_[hidden]
Date: 2011-05-27 04:46:34

Author: barendgehrels
Date: 2011-05-27 04:46:32 EDT (Fri, 27 May 2011)
New Revision: 72208
URL: http://svn.boost.org/trac/boost/changeset/72208

Log:
Added spherical side formula
Added:
   trunk/boost/geometry/strategies/spherical/ssf.hpp   (contents, props changed)
Text files modified: 
   trunk/boost/geometry/strategies/spherical/side_by_cross_track.hpp |    12 ------------                            
   1 files changed, 0 insertions(+), 12 deletions(-)

Modified: trunk/boost/geometry/strategies/spherical/side_by_cross_track.hpp
==============================================================================
--- trunk/boost/geometry/strategies/spherical/side_by_cross_track.hpp	(original)
+++ trunk/boost/geometry/strategies/spherical/side_by_cross_track.hpp	2011-05-27 04:46:32 EDT (Fri, 27 May 2011)
@@ -83,9 +83,6 @@
                 CalculationType
             >::type coordinate_type;
 
-        // Calculate the distance using the Haversine formula.
-        // That is also applicable on the spherical earth. A radius is not necessary.
-
         double d1 = 0.001; // m_strategy.apply(sp1, p);
         double crs_AD = detail::course(p1, p);
         double crs_AB = detail::course(p1, p2);
@@ -99,15 +96,6 @@
 }} // namespace strategy::side
 
 
-#ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
-template <typename CalculationType>
-struct strategy_side<spherical_tag, CalculationType>
-{
-    typedef strategy::side::side_by_cross_track<CalculationType> type;
-};
-#endif
-
-
 }} // namespace boost::geometry
 
 

Added: trunk/boost/geometry/strategies/spherical/ssf.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/geometry/strategies/spherical/ssf.hpp	2011-05-27 04:46:32 EDT (Fri, 27 May 2011)
@@ -0,0 +1,111 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+
+// Copyright (c) 2011 Barend Gehrels, Amsterdam, the Netherlands.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
+#define BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
+
+#include <boost/mpl/if.hpp>
+#include <boost/type_traits.hpp>
+
+#include <boost/geometry/core/cs.hpp>
+#include <boost/geometry/core/access.hpp>
+#include <boost/geometry/core/radian_access.hpp>
+
+#include <boost/geometry/util/select_coordinate_type.hpp>
+#include <boost/geometry/util/math.hpp>
+
+#include <boost/geometry/strategies/side.hpp>
+//#include <boost/geometry/strategies/concepts/side_concept.hpp>
+
+
+namespace boost { namespace geometry
+{
+
+
+namespace strategy { namespace side
+{
+
+
+/*!
+\brief Check at which side of a segment a point lies:
+\details from a Great Circle segment between two points:
+         left of segment (> 0), right of segment (< 0), on segment (0)
+\ingroup strategies
+\tparam CalculationType \tparam_calculation
+ */
+template <typename CalculationType = void>
+class spherical_side_formula
+{
+
+public :
+    template <typename P1, typename P2, typename P>
+    static inline int apply(P1 const& p1, P2 const& p2, P const& p)
+    {
+        typedef typename boost::mpl::if_c
+            <
+                boost::is_void<CalculationType>::type::value,
+
+                // Select at least a double...
+                typename select_most_precise
+                    <
+                        typename select_most_precise
+                            <
+                                typename select_most_precise
+                                    <
+                                        typename coordinate_type<P1>::type,
+                                        typename coordinate_type<P2>::type
+                                    >::type,
+                                typename coordinate_type<P>::type
+                            >::type,
+                        double
+                    >::type,
+                CalculationType
+            >::type coordinate_type;
+
+        // Convenient shortcuts
+        typedef coordinate_type ct;
+        ct const phi1 = get_as_radian<0>(p1);
+        ct const theta1 = get_as_radian<1>(p1);
+        ct const phi2 = get_as_radian<0>(p2);
+        ct const theta2 = get_as_radian<1>(p2);
+        ct const phi = get_as_radian<0>(p);
+        ct const theta = get_as_radian<1>(p);
+
+        // Create temporary points (vectors) on unit a sphere
+        ct const sin_theta1 = sin(theta1);
+        ct const c1x = sin_theta1 * cos(phi1);
+        ct const c1y = sin_theta1 * sin(phi1);
+        ct const c1z = cos(theta1);
+
+        ct const sin_theta2 = sin(theta2);
+        ct const c2x = sin_theta2 * cos(phi2);
+        ct const c2y = sin_theta2 * sin(phi2);
+        ct const c2z = cos(theta2);
+
+        // (Third point is converted directly)
+        ct const sin_theta = sin(theta);
+        
+        // Apply the "Spherical Side Formula" as presented on my blog
+        ct const dist 
+            = (c1y * c2z - c1z * c2y) * sin_theta * cos(phi) 
+            + (c1z * c2x - c1x * c2z) * sin_theta * sin(phi)
+            + (c1x * c2y - c1y * c2x) * cos(theta);
+            
+        return dist < 0 ? 1
+            : dist > 0 ? -1
+            : 0;
+    }
+};
+
+}} // namespace strategy::side
+
+
+}} // namespace boost::geometry
+
+
+#endif // BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP