diff --git a/include/boost/geometry/iterators/closing_iterator.hpp b/include/boost/geometry/iterators/closing_iterator.hpp
index fdb97977c..35fd1737c 100644
--- a/include/boost/geometry/iterators/closing_iterator.hpp
+++ b/include/boost/geometry/iterators/closing_iterator.hpp
@@ -4,7 +4,7 @@
 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
 
-// Copyright (c) 2020, Oracle and/or its affiliates.
+// Copyright (c) 2020-2021, Oracle and/or its affiliates.
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
@@ -24,9 +24,10 @@
 #include <boost/range/end.hpp>
 #include <boost/range/difference_type.hpp>
 #include <boost/range/reference.hpp>
-#include <boost/range/size.hpp>
 #include <boost/range/value_type.hpp>
 
+#include <boost/geometry/core/assert.hpp>
+
 
 namespace boost { namespace geometry
 {
@@ -66,31 +67,52 @@ public:
     typedef typename base_type::difference_type difference_type;
 
     /// Constructor including the range it is based on
-    explicit inline closing_iterator(Range& range)
-        : m_range(&range)
-        , m_iterator(boost::begin(range))
+    explicit inline closing_iterator(Range const& range)
+        : m_iterator(boost::begin(range))
+        , m_begin(boost::begin(range))
         , m_end(boost::end(range))
-        , m_size(static_cast<difference_type>(boost::size(range)))
+        , m_size(m_end - m_begin)
         , m_index(0)
     {}
 
     /// Constructor to indicate the end of a range
-    explicit inline closing_iterator(Range& range, bool)
-        : m_range(&range)
-        , m_iterator(boost::end(range))
+    explicit inline closing_iterator(Range const& range, bool)
+        : m_iterator(boost::end(range))
+        , m_begin(boost::begin(range))
         , m_end(boost::end(range))
-        , m_size(static_cast<difference_type>(boost::size(range)))
+        , m_size(m_end - m_begin)
         , m_index((m_size == 0) ? 0 : m_size + 1)
     {}
 
     /// Default constructor
-    explicit inline closing_iterator()
-        : m_range(NULL)
-        , m_size(0)
+    inline closing_iterator()
+        : m_size(0)
         , m_index(0)
     {}
 
+    template
+    <
+        typename OtherRange,
+        std::enable_if_t
+            <
+                std::is_convertible
+                    <
+                        typename boost::range_iterator<OtherRange const>::type,
+                        typename boost::range_iterator<Range const>::type
+                    >::value,
+                int
+            > = 0
+    >
+    inline closing_iterator(closing_iterator<OtherRange> const& other)
+        : m_iterator(other.m_iterator)
+        , m_begin(other.m_begin)
+        , m_end(other.m_end)
+        , m_size(other.m_size)
+        , m_index(other.m_index)
+    {}
+
 private:
+    template <typename OtherRange> friend struct closing_iterator;
     friend class boost::iterator_core_access;
 
     inline reference dereference() const
@@ -105,8 +127,8 @@ private:
 
     inline bool equal(closing_iterator<Range> const& other) const
     {
-        return this->m_range == other.m_range
-            && this->m_index == other.m_index;
+        BOOST_GEOMETRY_ASSERT(m_begin == other.m_begin && m_end == other.m_end);
+        return this->m_index == other.m_index;
     }
 
     inline void increment()
@@ -150,14 +172,14 @@ private:
     inline void update_iterator()
     {
         this->m_iterator = m_index <= m_size
-            ? boost::begin(*m_range) + (m_index % m_size)
-            : boost::end(*m_range)
+            ? m_begin + (m_index % m_size)
+            : m_end
             ;
     }
 
-    Range* m_range;
-    typename boost::range_iterator<Range>::type m_iterator;
-    typename boost::range_iterator<Range>::type m_end;
+    typename boost::range_iterator<Range const>::type m_iterator;
+    typename boost::range_iterator<Range const>::type m_begin;
+    typename boost::range_iterator<Range const>::type m_end;
     difference_type m_size;
     difference_type m_index;
 };
diff --git a/include/boost/geometry/iterators/concatenate_iterator.hpp b/include/boost/geometry/iterators/concatenate_iterator.hpp
index a6cfa8ee7..d3266e975 100644
--- a/include/boost/geometry/iterators/concatenate_iterator.hpp
+++ b/include/boost/geometry/iterators/concatenate_iterator.hpp
@@ -1,6 +1,6 @@
 // Boost.Geometry (aka GGL, Generic Geometry Library)
 
-// Copyright (c) 2014-2020, Oracle and/or its affiliates.
+// Copyright (c) 2014-2021, Oracle and/or its affiliates.
 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
@@ -16,8 +16,6 @@
 #include <boost/iterator/iterator_facade.hpp>
 #include <boost/iterator/iterator_categories.hpp>
 
-#include <boost/geometry/core/static_assert.hpp>
-
 
 namespace boost { namespace geometry
 {
@@ -49,7 +47,7 @@ public:
     typedef Iterator2 second_iterator_type;
 
     // default constructor
-    concatenate_iterator() {}
+    concatenate_iterator() = default;
 
     // for begin
     concatenate_iterator(Iterator1 it1, Iterator1 end1,
@@ -67,7 +65,13 @@ public:
         typename OtherIt1,
         typename OtherIt2,
         typename OtherValue,
-        typename OtherReference
+        typename OtherReference,
+        std::enable_if_t
+            <
+                std::is_convertible<OtherIt1, Iterator1>::value
+                && std::is_convertible<OtherIt2, Iterator2>::value,
+                int
+            > = 0
     >
     concatenate_iterator(concatenate_iterator
                          <
@@ -80,15 +84,7 @@ public:
         , m_end1(other.m_end1)
         , m_begin2(other.m_begin2)
         , m_it2(other.m_it2)
-    {
-        static const bool are_conv
-            = std::is_convertible<OtherIt1, Iterator1>::value
-           && std::is_convertible<OtherIt2, Iterator2>::value;
-
-        BOOST_GEOMETRY_STATIC_ASSERT((are_conv),
-            "Other iterators have to be convertible to member iterators.",
-            OtherIt1, OtherIt2);
-    }
+    {}
 
 private:
     friend class boost::iterator_core_access;
diff --git a/include/boost/geometry/iterators/ever_circling_iterator.hpp b/include/boost/geometry/iterators/ever_circling_iterator.hpp
index 7492e1acc..ece1b6cdb 100644
--- a/include/boost/geometry/iterators/ever_circling_iterator.hpp
+++ b/include/boost/geometry/iterators/ever_circling_iterator.hpp
@@ -4,8 +4,8 @@
 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
 
-// This file was modified by Oracle on 2020.
-// Modifications copyright (c) 2020 Oracle and/or its affiliates.
+// This file was modified by Oracle on 2020-2021.
+// Modifications copyright (c) 2020-2021 Oracle and/or its affiliates.
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
@@ -18,6 +18,9 @@
 #ifndef BOOST_GEOMETRY_ITERATORS_EVER_CIRCLING_ITERATOR_HPP
 #define BOOST_GEOMETRY_ITERATORS_EVER_CIRCLING_ITERATOR_HPP
 
+
+#include <type_traits>
+
 #include <boost/iterator/iterator_adaptor.hpp>
 #include <boost/iterator/iterator_categories.hpp>
 #include <boost/range/begin.hpp>
@@ -26,8 +29,11 @@
 #include <boost/range/size.hpp>
 #include <boost/range/value_type.hpp>
 
+#include <boost/geometry/core/assert.hpp>
+
 #include <boost/geometry/iterators/base.hpp>
 
+
 namespace boost { namespace geometry
 {
 
@@ -49,7 +55,7 @@ struct ever_circling_iterator :
         Iterator
     >
 {
-    friend class boost::iterator_core_access;
+    ever_circling_iterator() = default;
 
     explicit inline ever_circling_iterator(Iterator begin, Iterator end,
             bool skip_first = false)
@@ -69,6 +75,17 @@ struct ever_circling_iterator :
         this->base_reference() = start;
     }
 
+    template
+    <
+        typename OtherIterator,
+        std::enable_if_t<std::is_convertible<OtherIterator, Iterator>::value, int> = 0
+    >
+    inline ever_circling_iterator(ever_circling_iterator<OtherIterator> const& other)
+        : m_begin(other.m_begin)
+        , m_end(other.m_end)
+        , m_skip_first(other.m_skip_first)
+    {}
+
     /// Navigate to a certain position, should be in [start .. end], if at end
     /// it will circle again.
     inline void moveto(Iterator it)
@@ -78,6 +95,8 @@ struct ever_circling_iterator :
     }
 
 private:
+    template <typename OtherIterator> friend struct ever_circling_iterator;
+    friend class boost::iterator_core_access;
 
     inline void increment(bool possibly_skip = true)
     {
@@ -125,8 +144,8 @@ private:
 
 public:
     /// Constructor including the range it is based on
-    explicit inline ever_circling_range_iterator(Range& range)
-        : m_range(&range)
+    explicit inline ever_circling_range_iterator(Range const& range)
+        : m_begin(boost::begin(range))
         , m_iterator(boost::begin(range))
         , m_size(boost::size(range))
         , m_index(0)
@@ -134,15 +153,35 @@ public:
 
     /// Default constructor
     explicit inline ever_circling_range_iterator()
-        : m_range(NULL)
-        , m_size(0)
+        : m_size(0)
         , m_index(0)
     {}
 
+    template
+    <
+        typename OtherRange,
+        std::enable_if_t
+            <
+                std::is_convertible
+                    <
+                        typename boost::range_iterator<OtherRange const>::type,
+                        typename boost::range_iterator<Range const>::type
+                    >::value,
+                int
+            > = 0
+    >
+    inline ever_circling_range_iterator(ever_circling_range_iterator<OtherRange> const& other)
+        : m_begin(other.m_begin)
+        , m_iterator(other.m_iterator)
+        , m_size(other.m_size)
+        , m_index(other.m_index)
+    {}
+
     typedef typename base_type::reference reference;
     typedef typename base_type::difference_type difference_type;
 
 private:
+    template <typename OtherRange> friend struct ever_circling_range_iterator;
     friend class boost::iterator_core_access;
 
     inline reference dereference() const
@@ -157,8 +196,8 @@ private:
 
     inline bool equal(ever_circling_range_iterator<Range> const& other) const
     {
-        return this->m_range == other.m_range
-            && this->m_index == other.m_index;
+        BOOST_GEOMETRY_ASSERT(m_begin == other.m_begin);
+        return this->m_index == other.m_index;
     }
 
     inline void increment()
@@ -209,11 +248,11 @@ private:
             m_index += m_size;
         }
         m_index = m_index % m_size;
-        this->m_iterator = boost::begin(*m_range) + m_index;
+        this->m_iterator = m_begin + m_index;
     }
 
-    Range* m_range;
-    typename boost::range_iterator<Range>::type m_iterator;
+    typename boost::range_iterator<Range const>::type m_begin;
+    typename boost::range_iterator<Range const>::type m_iterator;
     difference_type m_size;
     difference_type m_index;
 };
diff --git a/include/boost/geometry/iterators/flatten_iterator.hpp b/include/boost/geometry/iterators/flatten_iterator.hpp
index 190e59413..9b45d2efe 100644
--- a/include/boost/geometry/iterators/flatten_iterator.hpp
+++ b/include/boost/geometry/iterators/flatten_iterator.hpp
@@ -1,6 +1,6 @@
 // Boost.Geometry (aka GGL, Generic Geometry Library)
 
-// Copyright (c) 2014-2020, Oracle and/or its affiliates.
+// Copyright (c) 2014-2021, Oracle and/or its affiliates.
 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
@@ -10,13 +10,14 @@
 #ifndef BOOST_GEOMETRY_ITERATORS_FLATTEN_ITERATOR_HPP
 #define BOOST_GEOMETRY_ITERATORS_FLATTEN_ITERATOR_HPP
 
+
 #include <type_traits>
 
 #include <boost/iterator/iterator_facade.hpp>
 #include <boost/iterator/iterator_categories.hpp>
 
 #include <boost/geometry/core/assert.hpp>
-#include <boost/geometry/core/static_assert.hpp>
+
 
 namespace boost { namespace geometry
 {
@@ -58,7 +59,7 @@ public:
     typedef InnerIterator inner_iterator_type;
 
     // default constructor
-    flatten_iterator() {}
+    flatten_iterator() = default;
 
     // for begin
     flatten_iterator(OuterIterator outer_it, OuterIterator outer_end)
@@ -77,7 +78,13 @@ public:
         typename OtherOuterIterator, typename OtherInnerIterator,
         typename OtherValue,
         typename OtherAccessInnerBegin, typename OtherAccessInnerEnd,
-        typename OtherReference
+        typename OtherReference,
+        std::enable_if_t
+            <
+                std::is_convertible<OtherOuterIterator, OuterIterator>::value
+                && std::is_convertible<OtherInnerIterator, InnerIterator>::value,
+                int
+            > = 0
     >
     flatten_iterator(flatten_iterator
                      <
@@ -91,21 +98,7 @@ public:
         : m_outer_it(other.m_outer_it),
           m_outer_end(other.m_outer_end),
           m_inner_it(other.m_inner_it)
-    {
-        static const bool are_conv
-            = std::is_convertible
-                <
-                    OtherOuterIterator, OuterIterator
-                >::value
-           && std::is_convertible
-                <
-                    OtherInnerIterator, InnerIterator
-                >::value;
-
-        BOOST_GEOMETRY_STATIC_ASSERT((are_conv),
-            "Other iterators have to be convertible to member iterators.",
-            OtherOuterIterator, OtherInnerIterator);
-    }
+    {}
 
     flatten_iterator& operator=(flatten_iterator const& other)
     {
diff --git a/include/boost/geometry/iterators/point_iterator.hpp b/include/boost/geometry/iterators/point_iterator.hpp
index 12e1d85c2..4168797cf 100644
--- a/include/boost/geometry/iterators/point_iterator.hpp
+++ b/include/boost/geometry/iterators/point_iterator.hpp
@@ -1,6 +1,6 @@
 // Boost.Geometry (aka GGL, Generic Geometry Library)
 
-// Copyright (c) 2014-2020, Oracle and/or its affiliates.
+// Copyright (c) 2014-2021, Oracle and/or its affiliates.
 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
@@ -19,7 +19,6 @@
 
 #include <boost/geometry/core/exterior_ring.hpp>
 #include <boost/geometry/core/interior_rings.hpp>
-#include <boost/geometry/core/static_assert.hpp>
 #include <boost/geometry/core/tags.hpp>
 
 #include <boost/geometry/iterators/dispatch/point_iterator.hpp>
@@ -263,28 +262,24 @@ private:
         : point_iterator::iterator_adaptor_(base_it) {}
 
 public:
-    inline point_iterator() {}
+    inline point_iterator() = default;
 
-    template <typename OtherGeometry>
+    template
+    <
+        typename OtherGeometry,
+        std::enable_if_t
+            <
+                std::is_convertible
+                    <
+                        typename detail::point_iterator::iterator_type<OtherGeometry>::type,
+                        typename detail::point_iterator::iterator_type<Geometry>::type
+                    >::value,
+                int
+            > = 0
+    >
     inline point_iterator(point_iterator<OtherGeometry> const& other)
         : point_iterator::iterator_adaptor_(other.base())
-    {
-        static const bool is_conv
-            = std::is_convertible<
-                typename detail::point_iterator::iterator_type
-                    <
-                        OtherGeometry
-                    >::type,
-                typename detail::point_iterator::iterator_type
-                    <
-                        Geometry
-                    >::type
-            >::value;
-
-        BOOST_GEOMETRY_STATIC_ASSERT((is_conv),
-            "Other iterator has to be convertible to member iterator.",
-            point_iterator<OtherGeometry>);
-    }
+    {}
 };
 
 
diff --git a/include/boost/geometry/iterators/point_reverse_iterator.hpp b/include/boost/geometry/iterators/point_reverse_iterator.hpp
index f32dbf6ba..9c8cb492e 100644
--- a/include/boost/geometry/iterators/point_reverse_iterator.hpp
+++ b/include/boost/geometry/iterators/point_reverse_iterator.hpp
@@ -1,6 +1,6 @@
 // Boost.Geometry (aka GGL, Generic Geometry Library)
 
-// Copyright (c) 2014-2020, Oracle and/or its affiliates.
+// Copyright (c) 2014-2021, Oracle and/or its affiliates.
 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
@@ -13,7 +13,6 @@
 #include <iterator>
 #include <type_traits>
 
-#include <boost/geometry/core/static_assert.hpp>
 #include <boost/geometry/iterators/point_iterator.hpp>
 
 namespace boost { namespace geometry
@@ -39,23 +38,24 @@ private:
         : base_type(base_it) {}
 
 public:
-    inline point_reverse_iterator() {}
+    inline point_reverse_iterator() = default;
 
-    template <typename OtherGeometry>
-    inline
-    point_reverse_iterator(point_reverse_iterator<OtherGeometry> const& other)
-        : base_type(other.base())
-    {
-        static const bool is_conv = std::is_convertible
+    template
+    <
+        typename OtherGeometry,
+        std::enable_if_t
             <
-                std::reverse_iterator<point_iterator<Geometry> >,
-                std::reverse_iterator<point_iterator<OtherGeometry> >
-            >::value;
-
-        BOOST_GEOMETRY_STATIC_ASSERT((is_conv),
-            "Other iterator has to be convertible to member iterator.",
-            point_reverse_iterator<OtherGeometry>);
-    }
+                std::is_convertible
+                    <
+                        std::reverse_iterator<point_iterator<OtherGeometry> >,
+                        std::reverse_iterator<point_iterator<Geometry> >
+                    >::value,
+                int
+            > = 0
+    >
+    inline point_reverse_iterator(point_reverse_iterator<OtherGeometry> const& other)
+        : base_type(other.base())
+    {}
 };
 
 
diff --git a/include/boost/geometry/iterators/segment_iterator.hpp b/include/boost/geometry/iterators/segment_iterator.hpp
index cd59321db..84af76e9c 100644
--- a/include/boost/geometry/iterators/segment_iterator.hpp
+++ b/include/boost/geometry/iterators/segment_iterator.hpp
@@ -1,6 +1,6 @@
 // Boost.Geometry (aka GGL, Generic Geometry Library)
 
-// Copyright (c) 2014-2020, Oracle and/or its affiliates.
+// Copyright (c) 2014-2021, Oracle and/or its affiliates.
 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
@@ -18,7 +18,6 @@
 
 #include <boost/geometry/core/exterior_ring.hpp>
 #include <boost/geometry/core/interior_rings.hpp>
-#include <boost/geometry/core/static_assert.hpp>
 #include <boost/geometry/core/tags.hpp>
 
 #include <boost/geometry/iterators/detail/point_iterator/inner_range_type.hpp>
@@ -285,25 +284,24 @@ public:
     // correct iterator category.
     typedef std::bidirectional_iterator_tag iterator_category;
 
-    inline segment_iterator() {}
+    inline segment_iterator() = default;
 
-    template <typename OtherGeometry>
+    template
+    <
+        typename OtherGeometry,
+        std::enable_if_t
+            <
+                std::is_convertible
+                    <
+                        typename detail::segment_iterator::iterator_type<OtherGeometry>::type,
+                        typename detail::segment_iterator::iterator_type<Geometry>::type
+                    >::value,
+                int
+            > = 0
+    >
     inline segment_iterator(segment_iterator<OtherGeometry> const& other)
         : base(*other.base_ptr())
-    {
-        static const bool is_conv
-            = std::is_convertible<
-                typename detail::segment_iterator::iterator_type
-                    <
-                        OtherGeometry
-                    >::type,
-                typename detail::segment_iterator::iterator_type<Geometry>::type
-            >::value;
-
-        BOOST_GEOMETRY_STATIC_ASSERT((is_conv),
-            "Other iterator has to be convertible to member iterator.",
-            segment_iterator<OtherGeometry>);
-    }
+    {}
 
     inline segment_iterator& operator++() // prefix
     {
diff --git a/include/boost/geometry/views/closeable_view.hpp b/include/boost/geometry/views/closeable_view.hpp
index ba5bbd3f8..6114bc0e2 100644
--- a/include/boost/geometry/views/closeable_view.hpp
+++ b/include/boost/geometry/views/closeable_view.hpp
@@ -4,8 +4,8 @@
 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
 
-// This file was modified by Oracle on 2020.
-// Modifications copyright (c) 2020 Oracle and/or its affiliates.
+// This file was modified by Oracle on 2020-2021.
+// Modifications copyright (c) 2020-2021 Oracle and/or its affiliates.
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
@@ -43,21 +43,24 @@ namespace detail
 template <typename Range>
 struct closing_view
 {
+    using iterator = closing_iterator<Range>;
+    using const_iterator = closing_iterator<Range const>;
+
     // Keep this explicit, important for nested views/ranges
     explicit inline closing_view(Range& r)
-        : m_range(r)
+        : m_begin(r)
+        , m_end(r, true)
     {}
 
-    typedef closing_iterator<Range> iterator;
-    typedef closing_iterator<Range const> const_iterator;
+    inline const_iterator begin() const { return m_begin; }
+    inline const_iterator end() const { return m_end; }
 
-    inline const_iterator begin() const { return const_iterator(m_range); }
-    inline const_iterator end() const { return const_iterator(m_range, true); }
+    inline iterator begin() { return m_begin; }
+    inline iterator end() { return m_end; }
 
-    inline iterator begin() { return iterator(m_range); }
-    inline iterator end() { return iterator(m_range, true); }
-private :
-    Range& m_range;
+private:
+    iterator m_begin;
+    iterator m_end;
 };
 
 }
diff --git a/include/boost/geometry/views/detail/normalized_view.hpp b/include/boost/geometry/views/detail/normalized_view.hpp
index 2d3d4a8ba..e0063ca4f 100644
--- a/include/boost/geometry/views/detail/normalized_view.hpp
+++ b/include/boost/geometry/views/detail/normalized_view.hpp
@@ -4,8 +4,8 @@
 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
 
-// This file was modified by Oracle on 2014-2020.
-// Modifications copyright (c) 2014-2020 Oracle and/or its affiliates.
+// This file was modified by Oracle on 2014-2021.
+// Modifications copyright (c) 2014-2021 Oracle and/or its affiliates.
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
@@ -28,6 +28,7 @@
 #include <boost/geometry/views/reversible_view.hpp>
 #include <boost/geometry/views/closeable_view.hpp>
 #include <boost/geometry/util/order_as_direction.hpp>
+#include <boost/geometry/util/type_traits_std.hpp>
 
 namespace boost { namespace geometry {
 
@@ -39,53 +40,30 @@ namespace detail {
 template <typename Geometry>
 struct normalized_view
 {
-    static const bool is_const = std::is_const<Geometry>::value;
+    using range_type = typename detail::range_type<Geometry>::type;
+    using range = util::transcribe_const_t<Geometry, range_type>;
 
-    //typedef typename ring_type<Geometry>::type ring_type;
-
-    typedef typename detail::range_type<Geometry>::type range_type;
-
-    typedef std::conditional_t
-        <
-            is_const,
-            range_type const,
-            range_type
-        > range;
-
-    typedef typename
-        reversible_view
+    using reversible_type = typename reversible_view
             <
                 range,
                 order_as_direction
                     <
                         geometry::point_order<Geometry>::value
                     >::value
-            >::type reversible_type;
+            >::type;
 
-    typedef std::conditional_t
-        <
-            is_const,
-            reversible_type const,
-            reversible_type
-        > reversible;
-
-    typedef typename
-        closeable_view
+    using reversible = util::transcribe_const_t<Geometry, reversible_type>;
+    
+    using closeable_type = typename closeable_view
             <
                 reversible,
                 geometry::closure<Geometry>::value
-            >::type closeable_type;
+            >::type;
 
-    typedef std::conditional_t
-        <
-            is_const,
-            closeable_type const,
-            closeable_type
-        > closeable;
+    using closeable = util::transcribe_const_t<Geometry, closeable_type>;
     
     explicit inline normalized_view(range & r)
-        : m_reversible(r)
-        , m_closeable(m_reversible)
+        : m_closeable(reversible_type(r))
     {}
 
     typedef typename boost::range_iterator<closeable>::type iterator;
@@ -98,7 +76,6 @@ struct normalized_view
     inline iterator end() { return boost::end(m_closeable); }
 
 private:
-    reversible_type m_reversible;
     closeable_type m_closeable;
 };
 
diff --git a/include/boost/geometry/views/identity_view.hpp b/include/boost/geometry/views/identity_view.hpp
index a05b54326..ebdb2ec75 100644
--- a/include/boost/geometry/views/identity_view.hpp
+++ b/include/boost/geometry/views/identity_view.hpp
@@ -4,8 +4,8 @@
 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
 
-// This file was modified by Oracle on 2020.
-// Modifications copyright (c) 2020 Oracle and/or its affiliates.
+// This file was modified by Oracle on 2020-2021.
+// Modifications copyright (c) 2020-2021 Oracle and/or its affiliates.
 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
 
 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
@@ -18,6 +18,7 @@
 #ifndef BOOST_GEOMETRY_VIEWS_IDENTITY_VIEW_HPP
 #define BOOST_GEOMETRY_VIEWS_IDENTITY_VIEW_HPP
 
+#include <boost/range/iterator_range.hpp>
 
 #include <boost/range/begin.hpp>
 #include <boost/range/end.hpp>
@@ -40,20 +41,23 @@ namespace boost { namespace geometry
 template <typename Range>
 struct identity_view
 {
-    typedef typename boost::range_iterator<Range const>::type const_iterator;
-    typedef typename boost::range_iterator<Range>::type iterator;
+    using const_iterator = typename boost::range_iterator<Range const>::type;
+    using iterator = typename boost::range_iterator<Range>::type;
 
     explicit inline identity_view(Range& r)
-        : m_range(r)
+        : m_begin(boost::begin(r))
+        , m_end(boost::end(r))
     {}
 
-    inline const_iterator begin() const { return boost::begin(m_range); }
-    inline const_iterator end() const { return boost::end(m_range); }
+    inline const_iterator begin() const { return m_begin; }
+    inline const_iterator end() const { return m_end; }
 
-    inline iterator begin() { return boost::begin(m_range); }
-    inline iterator end() { return boost::end(m_range); }
-private :
-    Range& m_range;
+    inline iterator begin() { return m_begin; }
+    inline iterator end() { return m_end; }
+
+private:
+    iterator m_begin;
+    iterator m_end;
 };
 
 #if defined(_MSC_VER)
diff --git a/test/iterators/closing_iterator.cpp b/test/iterators/closing_iterator.cpp
index 9ac43634b..a071b755f 100644
--- a/test/iterators/closing_iterator.cpp
+++ b/test/iterators/closing_iterator.cpp
@@ -5,6 +5,9 @@
 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
 
+// Copyright (c) 2021, Oracle and/or its affiliates.
+// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
+
 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
 
@@ -14,21 +17,49 @@
 
 #include <algorithm>
 #include <iterator>
-#include <sstream>
-#include <string>
 
 #include <geometry_test_common.hpp>
 
 #include <boost/geometry/iterators/closing_iterator.hpp>
 
-#include <boost/geometry/core/coordinate_type.hpp>
-#include <boost/geometry/io/wkt/read.hpp>
-#include <boost/geometry/geometries/geometries.hpp>
 #include <boost/geometry/geometries/point_xy.hpp>
+#include <boost/geometry/geometries/ring.hpp>
 
 #include <boost/range/adaptor/transformed.hpp>
 
 
+void test_concept()
+{
+    std::vector<int> v = {1, 2, 3};
+
+    using iterator = bg::closing_iterator<std::vector<int>>;
+    using const_iterator = bg::closing_iterator<std::vector<int> const>;
+
+    iterator it, it2(v);
+    const_iterator cit, cit2(v);
+
+    BOOST_CHECK((std::is_same<decltype(*it2), const int&>::value));
+    BOOST_CHECK((std::is_same<decltype(*cit2), const int&>::value));
+
+    it = it2;
+    cit = cit2;
+    BOOST_CHECK_EQUAL(*it, 1);
+    BOOST_CHECK_EQUAL(*cit, 1);
+    cit = ++it;
+    BOOST_CHECK_EQUAL(*it, 2);
+    BOOST_CHECK_EQUAL(*cit, 2);
+    // This is ok because both of these iterators are in fact const iterators
+    it = ++cit;
+    BOOST_CHECK_EQUAL(*it, 3);
+    BOOST_CHECK_EQUAL(*cit, 3);
+
+    // Check compilations, it is (since Oct 2010) random access
+    it--;
+    --it;
+    it += 2;
+    it -= 2;
+}
+
 // The closing iterator should also work on normal std:: containers
 void test_empty_non_geometry()
 {
@@ -39,49 +70,33 @@ void test_empty_non_geometry()
             std::vector<int> const
         > closing_iterator;
 
-
     closing_iterator it(v);
     closing_iterator end(v, true);
 
-    std::ostringstream out;
-    for (; it != end; ++it)
-    {
-        out << *it;
-    }
-    BOOST_CHECK_EQUAL(out.str(), "");
+    BOOST_CHECK(it == end);
 }
 
 void test_non_geometry()
 {
-    std::vector<int> v;
-    v.push_back(1);
-    v.push_back(2);
-    v.push_back(3);
-
+    std::vector<int> v = {1, 2, 3};
+    std::vector<int> closed_v = { 1, 2, 3, 1 };
+    
     typedef bg::closing_iterator
         <
             std::vector<int> const
         > closing_iterator;
 
-
     closing_iterator it(v);
     closing_iterator end(v, true);
-
-    std::ostringstream out;
-    for (; it != end; ++it)
-    {
-        out << *it;
-    }
-    BOOST_CHECK_EQUAL(out.str(), "1231");
+    
+    BOOST_CHECK(std::equal(it, end, closed_v.begin(), closed_v.end()));
 }
 
 void test_transformed_non_geometry()
 {
-    std::vector<int> v;
-    v.push_back(-1);
-    v.push_back(-2);
-    v.push_back(-3);
-
+    std::vector<int> v = {-1, -2, -3};
+    std::vector<int> closed_v = { 1, 2, 3, 1 };
+    
     typedef boost::transformed_range
         <
             std::negate<int>,
@@ -97,78 +112,50 @@ void test_transformed_non_geometry()
     closing_iterator it(v2);
     closing_iterator end(v2, true);
 
-    std::ostringstream out;
-    for (; it != end; ++it)
-    {
-        out << *it;
-    }
-    BOOST_CHECK_EQUAL(out.str(), "1231");
+    BOOST_CHECK(std::equal(it, end, closed_v.begin(), closed_v.end()));
 }
 
-
-
-
-
-template <typename Geometry>
-void test_geometry(std::string const& wkt)
+template <typename P>
+void test_geometry()
 {
-    Geometry geometry;
-    bg::read_wkt(wkt, geometry);
-    typedef bg::closing_iterator<Geometry const> closing_iterator;
+    bg::model::ring<P> geometry = { {1, 1}, {1, 4}, {4, 4}, {4, 1} };
+    bg::model::ring<P> closed = { {1, 1}, {1, 4}, {4, 4}, {4, 1}, {1, 1} };
+    
+    using closing_iterator = bg::closing_iterator<bg::model::ring<P> const>;
 
+    auto pred = [](P const& p1, P const& p2)
+        {
+            return bg::get<0>(p1) == bg::get<0>(p2) && bg::get<1>(p1) == bg::get<1>(p2);
+        };
 
     // 1. Test normal behaviour
     {
         closing_iterator it(geometry);
         closing_iterator end(geometry, true);
 
-        std::ostringstream out;
-        for (; it != end; ++it)
-        {
-            out << " " << bg::get<0>(*it) << bg::get<1>(*it);
-        }
-        BOOST_CHECK_EQUAL(out.str(), " 11 14 44 41 11");
-
-        // Check compilations, it is (since Oct 2010) random access
-        it--;
-        --it;
-        it += 2;
-        it -= 2;
+        BOOST_CHECK((std::equal(it, end, closed.begin(), closed.end(), pred)));
     }
 
     // 2: check copy behaviour
     {
-        typedef typename boost::range_iterator<Geometry const>::type normal_iterator;
-        Geometry copy;
+        bg::model::ring<P> copy;
 
-        std::copy<closing_iterator>(
-            closing_iterator(geometry),
-            closing_iterator(geometry, true),
-            std::back_inserter(copy));
+        std::copy(closing_iterator(geometry), closing_iterator(geometry, true),
+                  std::back_inserter(copy));
 
-        std::ostringstream out;
-        for (normal_iterator cit = boost::begin(copy); cit != boost::end(copy); ++cit)
-        {
-                out << " " << bg::get<0>(*cit) << bg::get<1>(*cit);
-        }
-        BOOST_CHECK_EQUAL(out.str(), " 11 14 44 41 11");
+        BOOST_CHECK((std::equal(copy.begin(), copy.end(), closed.begin(), closed.end(), pred)));
     }
 }
 
 
-template <typename P>
-void test_all()
-{
-    test_empty_non_geometry();
-    test_non_geometry();
-    test_transformed_non_geometry();
-    test_geometry<bg::model::ring<P> >("POLYGON((1 1,1 4,4 4,4 1))");
-}
-
-
 int test_main(int, char* [])
 {
-    test_all<bg::model::d2::point_xy<double> >();
+    test_concept();
+    test_empty_non_geometry();
+    test_non_geometry();
+    test_transformed_non_geometry();
+
+    test_geometry<bg::model::d2::point_xy<double>>();
 
     return 0;
 }