refactor: align C++ API naming with Python shapely

- Rename sym_difference → symmetric_difference (all 7 geometry types)
- Add boundary() to Point, LineString, LinearRing
- Add minimum_clearance() to Point, LineString, Polygon, LinearRing
- Add is_closed() to Point, Polygon
- Add is_ring() to Point, Polygon
- Add envelope() to LineString, LinearRing
- Add representative_point() to LineString, LinearRing
- Add project() / interpolate() to Polygon, LinearRing
- Expand LinearRing with full Python-equivalent API (buffer, distance,
  predicates, relates, hausdorff, constructive ops, convex_hull,
  parallel_offset, etc.)
- All 162 tests pass

Author: peng.li24

shapely/geometry/geometrycollection.h

@@ -48,7 +48,7 @@ class GeometryCollection {
     GeometryCollection difference(const GeometryCollection& other) const;
     GeometryCollection intersection(const GeometryCollection& other) const;
     GeometryCollection union_op(const GeometryCollection& other) const;
-    GeometryCollection sym_difference(const GeometryCollection& other) const;
+    GeometryCollection symmetric_difference(const GeometryCollection& other) const;
     GeometryCollection simplify(double tolerance) const;
 
     // -- Accessors --
@@ -155,7 +155,7 @@ GeometryCollection GeometryCollection::OP(const GeometryCollection& o) const { \
 GC_CONSTRUCT(difference,       geos_difference)
 GC_CONSTRUCT(intersection,     geos_intersection)
 GC_CONSTRUCT(union_op,         geos_union)
-GC_CONSTRUCT(sym_difference,   geos_sym_difference)
+GC_CONSTRUCT(symmetric_difference,   geos_sym_difference)
 #undef GC_CONSTRUCT
 
 GeometryCollection GeometryCollection::simplify(double tol) const {

shapely/geometry/linestring.h

@@ -119,6 +119,19 @@ class LineString {
     Point<double> interpolate(double distance) const;
     Point<double> centroid() const;
     Polygon<double> buffer(double distance) const;
+
+    // -- Boundary (Python: .boundary) --
+    std::string boundary() const;
+
+    // -- Minimum clearance (Python: .minimum_clearance) --
+    double minimum_clearance() const;
+
+    // -- Envelope (Python: .envelope) --
+    Polygon<double> envelope() const;
+
+    // -- Representative point (Python: .representative_point) --
+    Point<double> representative_point() const;
+
     void normalize();
 
     // -- Constructive operations (Python: difference, union, intersection, sym_difference) --
@@ -131,9 +144,9 @@ class LineString {
     std::string union_op(const LineString& other) const;
     template <typename U> std::string union_op(const Point<U>& other) const;
     template <typename U> std::string union_op(const Polygon<U>& other) const;
-    std::string sym_difference(const LineString& other) const;
-    template <typename U> std::string sym_difference(const Point<U>& other) const;
-    template <typename U> std::string sym_difference(const Polygon<U>& other) const;
+    std::string symmetric_difference(const LineString& other) const;
+    template <typename U> std::string symmetric_difference(const Point<U>& other) const;
+    template <typename U> std::string symmetric_difference(const Polygon<U>& other) const;
     std::string simplify(double tolerance) const;
     std::string parallel_offset(double distance, int quad_segs = 16) const;
     Polygon<double> convex_hull() const;
@@ -372,7 +385,7 @@ template <typename T> template <typename U> std::string LineString<T>::OP(const
 LS_CONSTRUCT(difference,       geos_difference)
 LS_CONSTRUCT(intersection,     geos_intersection)
 LS_CONSTRUCT(union_op,         geos_union)
-LS_CONSTRUCT(sym_difference,   geos_sym_difference)
+LS_CONSTRUCT(symmetric_difference,   geos_sym_difference)
 #undef LS_CONSTRUCT
 
 // Python: base.py::simplify:L469
@@ -404,6 +417,44 @@ Polygon<double> LineString<T>::convex_hull() const {
     return Polygon<double>(c.data(), n, 2);
 }
 
+// Python: shapely/geometry/base.py::boundary:L457
+template <typename T>
+std::string LineString<T>::boundary() const {
+    auto res = detail::geos_boundary(geos_linestring_.get());
+    return res ? detail::geos_to_wkt(res.get()) : "GEOMETRYCOLLECTION EMPTY";
+}
+
+// Python: shapely/geometry/base.py::minimum_clearance:L734
+template <typename T>
+double LineString<T>::minimum_clearance() const {
+    return detail::geos_minimum_clearance(geos_linestring_.get());
+}
+
+// Python: shapely/geometry/base.py::envelope:L742
+template <typename T>
+Polygon<double> LineString<T>::envelope() const {
+    auto res = detail::geos_envelope(geos_linestring_.get());
+    if (!res || res->isEmpty()) return Polygon<double>();
+    auto* gp = dynamic_cast<geos::geom::Polygon*>(res.get());
+    if (!gp) return Polygon<double>();
+    auto* cs = gp->getExteriorRing()->getCoordinatesRO();
+    if (!cs || cs->isEmpty()) return Polygon<double>();
+    size_t n = cs->getSize();
+    std::vector<double> c(n*2);
+    for (size_t i = 0; i < n; ++i) { c[i*2]=cs->getAt(i).x; c[i*2+1]=cs->getAt(i).y; }
+    return Polygon<double>(c.data(), n, 2);
+}
+
+// Python: shapely/geometry/base.py::representative_point:L877
+template <typename T>
+Point<double> LineString<T>::representative_point() const {
+    auto res = detail::geos_representative_point(geos_linestring_.get());
+    if (!res || res->isEmpty()) return Point<double>(0, 0);
+    auto* pt = dynamic_cast<geos::geom::Point*>(res.get());
+    if (!pt) return Point<double>(0, 0);
+    return Point<double>(pt->getX(), pt->getY());
+}
+
 // Python: base.py::normalize:L663
 template <typename T>
 void LineString<T>::normalize() { geos_linestring_->normalize(); }

shapely/geometry/multilinestring.h

@@ -96,7 +96,7 @@ class MultiLineString {
     MultiLineString<double> difference(const MultiLineString<double>& other) const;
     MultiLineString<double> intersection(const MultiLineString<double>& other) const;
     MultiLineString<double> union_op(const MultiLineString<double>& other) const;
-    MultiLineString<double> sym_difference(const MultiLineString<double>& other) const;
+    MultiLineString<double> symmetric_difference(const MultiLineString<double>& other) const;
     MultiLineString<double> simplify(double tolerance) const;
 
     // -- Accessors --
@@ -332,7 +332,7 @@ MultiLineString<double> MultiLineString<T>::union_op(const MultiLineString<doubl
     return MultiLineString<double>();
 }
 template <typename T>
-MultiLineString<double> MultiLineString<T>::sym_difference(const MultiLineString<double>& o) const {
+MultiLineString<double> MultiLineString<T>::symmetric_difference(const MultiLineString<double>& o) const {
     auto res = detail::geos_sym_difference(geos_mls_.get(), o.geos_mls_.get());
     if (!res || res->isEmpty()) return MultiLineString<double>();
     auto* mls = dynamic_cast<geos::geom::MultiLineString*>(res.get());

shapely/geometry/multipoint.h

@@ -87,8 +87,8 @@ class MultiPoint {
     template <typename U> Point<double> intersection(const Point<U>& other) const;
     MultiPoint<double> union_op(const MultiPoint<double>& other) const;
     template <typename U> MultiPoint<double> union_op(const Point<U>& other) const;
-    MultiPoint<double> sym_difference(const MultiPoint<double>& other) const;
-    template <typename U> MultiPoint<double> sym_difference(const Point<U>& other) const;
+    MultiPoint<double> symmetric_difference(const MultiPoint<double>& other) const;
+    template <typename U> MultiPoint<double> symmetric_difference(const Point<U>& other) const;
     MultiPoint<double> simplify(double tolerance) const;
 
     // -- Accessors --
@@ -339,7 +339,7 @@ MultiPoint<double> MultiPoint<T>::union_op(const Point<U>& o) const {
     return MultiPoint<double>(c.data(), n, 2);
 }
 template <typename T>
-MultiPoint<double> MultiPoint<T>::sym_difference(const MultiPoint<double>& o) const {
+MultiPoint<double> MultiPoint<T>::symmetric_difference(const MultiPoint<double>& o) const {
     auto res = detail::geos_sym_difference(geos_multipoint_.get(), o.geos_multipoint_.get());
     if (!res || res->isEmpty()) return MultiPoint<double>();
     auto* mpt = dynamic_cast<geos::geom::MultiPoint*>(res.get());
@@ -353,7 +353,7 @@ MultiPoint<double> MultiPoint<T>::sym_difference(const MultiPoint<double>& o) co
     return MultiPoint<double>(c.data(), n, 2);
 }
 template <typename T> template <typename U>
-MultiPoint<double> MultiPoint<T>::sym_difference(const Point<U>& o) const {
+MultiPoint<double> MultiPoint<T>::symmetric_difference(const Point<U>& o) const {
     auto res = detail::geos_sym_difference(geos_multipoint_.get(), o.geos_point_.get());
     if (!res || res->isEmpty()) return MultiPoint<double>();
     auto* mpt = dynamic_cast<geos::geom::MultiPoint*>(res.get());

shapely/geometry/multipolygon.h

@@ -113,7 +113,7 @@ class MultiPolygon {
     MultiPolygon<double> difference(const MultiPolygon<double>& other) const;
     MultiPolygon<double> intersection(const MultiPolygon<double>& other) const;
     MultiPolygon<double> union_op(const MultiPolygon<double>& other) const;
-    MultiPolygon<double> sym_difference(const MultiPolygon<double>& other) const;
+    MultiPolygon<double> symmetric_difference(const MultiPolygon<double>& other) const;
     MultiPolygon<double> simplify(double tolerance) const;
 
     // -- Accessors --
@@ -313,7 +313,7 @@ template <typename T> MultiPolygon<double> MultiPolygon<T>::OP(const MultiPolygo
 MPY_CONSTRUCT(difference,       geos_difference)
 MPY_CONSTRUCT(intersection,     geos_intersection)
 MPY_CONSTRUCT(union_op,         geos_union)
-MPY_CONSTRUCT(sym_difference,   geos_sym_difference)
+MPY_CONSTRUCT(symmetric_difference,   geos_sym_difference)
 #undef MPY_CONSTRUCT
 
 template <typename T>

shapely/geometry/point.h

@@ -43,6 +43,12 @@ class Point {
     // -- Buffer (Python: buffer) --
     Polygon<double> buffer(double distance) const;
 
+    // -- Boundary (Python: .boundary) --
+    std::string boundary() const;
+
+    // -- Minimum clearance (Python: .minimum_clearance) --
+    double minimum_clearance() const;
+
     // -- Predicates (Python: contains, within, ...) --
     template <typename U> bool contains(const Point<U>& other) const;
     template <typename U> bool contains(const LineString<U>& other) const;
@@ -103,6 +109,8 @@ class Point {
     bool is_empty() const;
     bool is_simple() const;
     bool is_valid() const;
+    bool is_closed() const;
+    bool is_ring() const;
     double area() const;
     double length() const;
     std::vector<double> bounds() const;
@@ -117,9 +125,9 @@ class Point {
     Point<double> union_op(const Point& other) const;
     template <typename U> std::string union_op(const LineString<U>& other) const;
     template <typename U> std::string union_op(const Polygon<U>& other) const;
-    Point<double> sym_difference(const Point& other) const;
-    template <typename U> std::string sym_difference(const LineString<U>& other) const;
-    template <typename U> std::string sym_difference(const Polygon<U>& other) const;
+    Point<double> symmetric_difference(const Point& other) const;
+    template <typename U> std::string symmetric_difference(const LineString<U>& other) const;
+    template <typename U> std::string symmetric_difference(const Polygon<U>& other) const;
     Point<double> simplify(double tolerance) const;
 
     // -- Topology (Python: convex_hull, boundary, envelope, representative_point) --
@@ -230,6 +238,19 @@ Polygon<double> Point<T>::buffer(double distance) const {
     return Polygon<double>(c.data(), n, 2);
 }
 
+// Python: shapely/geometry/base.py::boundary:L457
+template <typename T>
+std::string Point<T>::boundary() const {
+    // Point has no boundary — returns empty geometry
+    return "GEOMETRYCOLLECTION EMPTY";
+}
+
+// Python: shapely/geometry/base.py::minimum_clearance:L734
+template <typename T>
+double Point<T>::minimum_clearance() const {
+    return detail::geos_minimum_clearance(geos_point_.get());
+}
+
 // Python: shapely/geometry/base.py predicates L753-L813
 // -- Predicates (macros to reduce boilerplate) -------------------------------
 
@@ -391,7 +412,7 @@ std::string Point<T>::union_op(const Polygon<U>& o) const {
 }
 
 template <typename T>
-Point<double> Point<T>::sym_difference(const Point& o) const {
+Point<double> Point<T>::symmetric_difference(const Point& o) const {
     auto res = detail::geos_sym_difference(geos_point_.get(), o.geos_point_.get());
     if (!res || res->isEmpty()) return Point<double>(0, 0);
     auto* mpt = dynamic_cast<geos::geom::MultiPoint*>(res.get());
@@ -404,12 +425,12 @@ Point<double> Point<T>::sym_difference(const Point& o) const {
     return Point<double>(0, 0);
 }
 template <typename T> template <typename U>
-std::string Point<T>::sym_difference(const LineString<U>& o) const {
+std::string Point<T>::symmetric_difference(const LineString<U>& o) const {
     auto res = detail::geos_sym_difference(geos_point_.get(), o.geos_linestring_.get());
     return res ? detail::geos_to_wkt(res.get()) : "GEOMETRYCOLLECTION EMPTY";
 }
 template <typename T> template <typename U>
-std::string Point<T>::sym_difference(const Polygon<U>& o) const {
+std::string Point<T>::symmetric_difference(const Polygon<U>& o) const {
     auto res = detail::geos_sym_difference(geos_point_.get(), o.geos_polygon_.get());
     return res ? detail::geos_to_wkt(res.get()) : "GEOMETRYCOLLECTION EMPTY";
 }