From 2ecf2d393af173b997f4b60d7ffd27f0e9b18746 Mon Sep 17 00:00:00 2001
From: Menelaos Karavelas <menelaos.karavelas@gmail.com>
Date: Mon, 1 Jun 2015 13:10:45 +0300
Subject: [PATCH 1/4] [policies][rescale policy] initialize the rescale policy
 only if the input geometries are non-empty; this fixes unit test failures
 (union, intersection, difference) when BOOST_GEOMETRY_ENABLE_ACCESS_DEBUGGING
 is enabled;

---
 .../robustness/get_rescale_policy.hpp         | 34 ++++++++++++++++---
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/include/boost/geometry/policies/robustness/get_rescale_policy.hpp b/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
index 52570995f..0a1d7e355 100644
--- a/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
+++ b/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
@@ -27,6 +27,7 @@
 
 #include <boost/geometry/algorithms/envelope.hpp>
 #include <boost/geometry/algorithms/expand.hpp>
+#include <boost/geometry/algorithms/num_points.hpp>
 #include <boost/geometry/algorithms/detail/recalculate.hpp>
 #include <boost/geometry/algorithms/detail/get_max_size.hpp>
 #include <boost/geometry/policies/robustness/robust_type.hpp>
@@ -86,6 +87,11 @@ static inline void init_rescale_policy(Geometry const& geometry,
         RobustPoint& min_robust_point,
         Factor& factor)
 {
+    if (geometry::num_points(geometry) == 0)
+    {
+        return;
+    }
+
     // Get bounding boxes
     model::box<Point> env = geometry::return_envelope<model::box<Point> >(geometry);
 
@@ -99,10 +105,30 @@ static inline void init_rescale_policy(Geometry1 const& geometry1,
         RobustPoint& min_robust_point,
         Factor& factor)
 {
-    // Get bounding boxes
-    model::box<Point> env = geometry::return_envelope<model::box<Point> >(geometry1);
-    model::box<Point> env2 = geometry::return_envelope<model::box<Point> >(geometry2);
-    geometry::expand(env, env2);
+    // Get bounding boxes (when at least one of the geometries is not empty)
+    model::box<Point> env;
+    if (geometry::num_points(geometry1) == 0
+        && geometry::num_points(geometry2) == 0)
+    {
+        return;
+    }
+    else if (geometry::num_points(geometry1) == 0)
+    {
+        geometry::envelope(geometry2, env);
+    }
+    else if (geometry::num_points(geometry2) == 0)
+    {
+        geometry::envelope(geometry1, env);
+    }
+    else
+    {
+        geometry::envelope(geometry1, env);
+        model::box<Point> env2 = geometry::return_envelope
+            <
+                model::box<Point>
+            >(geometry2);
+        geometry::expand(env, env2);
+    }
 
     scale_box_to_integer_range(env, min_point, min_robust_point, factor);
 }

From 87052dcebaf0c005e2b41ac02a799f508469ee2a Mon Sep 17 00:00:00 2001
From: Menelaos Karavelas <menelaos.karavelas@gmail.com>
Date: Mon, 1 Jun 2015 16:21:27 +0300
Subject: [PATCH 2/4] [policies][rescale policy] compute number of points of
 each geometry only once

---
 .../geometry/policies/robustness/get_rescale_policy.hpp  | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/boost/geometry/policies/robustness/get_rescale_policy.hpp b/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
index 0a1d7e355..1268d4cdb 100644
--- a/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
+++ b/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
@@ -107,16 +107,17 @@ static inline void init_rescale_policy(Geometry1 const& geometry1,
 {
     // Get bounding boxes (when at least one of the geometries is not empty)
     model::box<Point> env;
-    if (geometry::num_points(geometry1) == 0
-        && geometry::num_points(geometry2) == 0)
+    bool is_empty1 = (geometry::num_points(geometry1) == 0);
+    bool is_empty2 = (geometry::num_points(geometry2) == 0);
+    if (is_empty1 == 0 && is_empty2)
     {
         return;
     }
-    else if (geometry::num_points(geometry1) == 0)
+    else if (is_empty1)
     {
         geometry::envelope(geometry2, env);
     }
-    else if (geometry::num_points(geometry2) == 0)
+    else if (is_empty2)
     {
         geometry::envelope(geometry1, env);
     }

From da9b4c99392226e8e8fa0af256d2a632dd32273e Mon Sep 17 00:00:00 2001
From: Menelaos Karavelas <menelaos.karavelas@gmail.com>
Date: Mon, 1 Jun 2015 23:45:52 +0300
Subject: [PATCH 3/4] [policies][rescale policy] apply coding rules; polish
 code; fix conditional expression; add comment regarding the computation of
 the bounding box when the geometries are in the spherical equatorial or
 geographic coordinate system;

---
 .../policies/robustness/get_rescale_policy.hpp    | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/boost/geometry/policies/robustness/get_rescale_policy.hpp b/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
index 1268d4cdb..f985cf3bf 100644
--- a/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
+++ b/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
@@ -106,14 +106,15 @@ static inline void init_rescale_policy(Geometry1 const& geometry1,
         Factor& factor)
 {
     // Get bounding boxes (when at least one of the geometries is not empty)
-    model::box<Point> env;
-    bool is_empty1 = (geometry::num_points(geometry1) == 0);
-    bool is_empty2 = (geometry::num_points(geometry2) == 0);
-    if (is_empty1 == 0 && is_empty2)
+    bool const is_empty1 = geometry::num_points(geometry1) == 0;
+    bool const is_empty2 = geometry::num_points(geometry2) == 0;
+    if (is_empty1 && is_empty2)
     {
         return;
     }
-    else if (is_empty1)
+
+    model::box<Point> env;
+    if (is_empty1)
     {
         geometry::envelope(geometry2, env);
     }
@@ -123,6 +124,10 @@ static inline void init_rescale_policy(Geometry1 const& geometry1,
     }
     else
     {
+        // The following approach (envelope + expand) may not give the
+        // optimal MBR when then two geometries are in the spherical
+        // equatorial or geographic coordinate systems.
+        // TODO: implement envelope for two (or possibly more geometries)
         geometry::envelope(geometry1, env);
         model::box<Point> env2 = geometry::return_envelope
             <

From 32cf69186084c0fe7a7edf8025580c3f9af2085c Mon Sep 17 00:00:00 2001
From: Menelaos Karavelas <menelaos.karavelas@gmail.com>
Date: Wed, 3 Jun 2015 17:31:45 +0300
Subject: [PATCH 4/4] [policies][get_rescale_policy] replace use of
 num_points() by is_empty()

---
 .../geometry/policies/robustness/get_rescale_policy.hpp   | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/boost/geometry/policies/robustness/get_rescale_policy.hpp b/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
index f985cf3bf..e48fd28d6 100644
--- a/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
+++ b/include/boost/geometry/policies/robustness/get_rescale_policy.hpp
@@ -27,7 +27,7 @@
 
 #include <boost/geometry/algorithms/envelope.hpp>
 #include <boost/geometry/algorithms/expand.hpp>
-#include <boost/geometry/algorithms/num_points.hpp>
+#include <boost/geometry/algorithms/is_empty.hpp>
 #include <boost/geometry/algorithms/detail/recalculate.hpp>
 #include <boost/geometry/algorithms/detail/get_max_size.hpp>
 #include <boost/geometry/policies/robustness/robust_type.hpp>
@@ -87,7 +87,7 @@ static inline void init_rescale_policy(Geometry const& geometry,
         RobustPoint& min_robust_point,
         Factor& factor)
 {
-    if (geometry::num_points(geometry) == 0)
+    if (geometry::is_empty(geometry))
     {
         return;
     }
@@ -106,8 +106,8 @@ static inline void init_rescale_policy(Geometry1 const& geometry1,
         Factor& factor)
 {
     // Get bounding boxes (when at least one of the geometries is not empty)
-    bool const is_empty1 = geometry::num_points(geometry1) == 0;
-    bool const is_empty2 = geometry::num_points(geometry2) == 0;
+    bool const is_empty1 = geometry::is_empty(geometry1);
+    bool const is_empty2 = geometry::is_empty(geometry2);
     if (is_empty1 && is_empty2)
     {
         return;