Refs #34406 -- Added support for GDAL curved geometries.

Co-authored-by: Fabien Le Frapper <contact@fabienlefrapper.me>

6 files changed, 292 insertions, 23 deletions

diff --git a/django/contrib/gis/gdal/geometries.py b/django/contrib/gis/gdal/geometries.py
index 44e1026e3f..9e712037c0 100644
--- a/django/contrib/gis/gdal/geometries.py
+++ b/django/contrib/gis/gdal/geometries.py
@@ -64,6 +64,7 @@ class OGRGeometry(GDALBase):
     """Encapsulate an OGR geometry."""
 
     destructor = capi.destroy_geom
+    geos_support = True
 
     def __init__(self, geom_input, srs=None):
         """Initialize Geometry on either WKT or an OGR pointer as input."""
@@ -304,6 +305,19 @@ class OGRGeometry(GDALBase):
                 f"Input to 'set_measured' must be a boolean, got '{value!r}'."
             )
 
+    @property
+    def has_curve(self):
+        """Return True if the geometry is or has curve geometry."""
+        return capi.has_curve_geom(self.ptr, 0)
+
+    def get_linear_geometry(self):
+        """Return a linear version of this geometry."""
+        return OGRGeometry(capi.get_linear_geom(self.ptr, 0, None))
+
+    def get_curve_geometry(self):
+        """Return a curve version of this geometry."""
+        return OGRGeometry(capi.get_curve_geom(self.ptr, None))
+
     # #### SpatialReference-related Properties ####
 
     # The SRS property
@@ -360,9 +374,14 @@ class OGRGeometry(GDALBase):
     @property
     def geos(self):
         "Return a GEOSGeometry object from this OGRGeometry."
-        from django.contrib.gis.geos import GEOSGeometry
+        if self.geos_support:
+            from django.contrib.gis.geos import GEOSGeometry
 
-        return GEOSGeometry(self._geos_ptr(), self.srid)
+            return GEOSGeometry(self._geos_ptr(), self.srid)
+        else:
+            from django.contrib.gis.geos import GEOSException
+
+            raise GEOSException(f"GEOS does not support {self.__class__.__qualname__}.")
 
     @property
     def gml(self):
@@ -727,6 +746,18 @@ class Polygon(OGRGeometry):
         return sum(self[i].point_count for i in range(self.geom_count))
 
 
+class CircularString(LineString):
+    geos_support = False
+
+
+class CurvePolygon(Polygon):
+    geos_support = False
+
+
+class CompoundCurve(OGRGeometry):
+    geos_support = False
+
+
 # Geometry Collection base class.
 class GeometryCollection(OGRGeometry):
     "The Geometry Collection class."
@@ -788,6 +819,14 @@ class MultiPolygon(GeometryCollection):
     pass
 
 
+class MultiSurface(GeometryCollection):
+    geos_support = False
+
+
+class MultiCurve(GeometryCollection):
+    geos_support = False
+
+
 # Class mapping dictionary (using the OGRwkbGeometryType as the key)
 GEO_CLASSES = {
     1: Point,
@@ -797,7 +836,17 @@ GEO_CLASSES = {
     5: MultiLineString,
     6: MultiPolygon,
     7: GeometryCollection,
+    8: CircularString,
+    9: CompoundCurve,
+    10: CurvePolygon,
+    11: MultiCurve,
+    12: MultiSurface,
     101: LinearRing,
+    1008: CircularString,  # CIRCULARSTRING Z
+    1009: CompoundCurve,  # COMPOUNDCURVE Z
+    1010: CurvePolygon,  # CURVEPOLYGON Z
+    1011: MultiCurve,  # MULTICURVE Z
+    1012: MultiSurface,  # MULTICURVE Z
     2001: Point,  # POINT M
     2002: LineString,  # LINESTRING M
     2003: Polygon,  # POLYGON M
@@ -805,6 +854,11 @@ GEO_CLASSES = {
     2005: MultiLineString,  # MULTILINESTRING M
     2006: MultiPolygon,  # MULTIPOLYGON M
     2007: GeometryCollection,  # GEOMETRYCOLLECTION M
+    2008: CircularString,  # CIRCULARSTRING M
+    2009: CompoundCurve,  # COMPOUNDCURVE M
+    2010: CurvePolygon,  # CURVEPOLYGON M
+    2011: MultiCurve,  # MULTICURVE M
+    2012: MultiSurface,  # MULTICURVE M
     3001: Point,  # POINT ZM
     3002: LineString,  # LINESTRING ZM
     3003: Polygon,  # POLYGON ZM
@@ -812,6 +866,11 @@ GEO_CLASSES = {
     3005: MultiLineString,  # MULTILINESTRING ZM
     3006: MultiPolygon,  # MULTIPOLYGON ZM
     3007: GeometryCollection,  # GEOMETRYCOLLECTION ZM
+    3008: CircularString,  # CIRCULARSTRING ZM
+    3009: CompoundCurve,  # COMPOUNDCURVE ZM
+    3010: CurvePolygon,  # CURVEPOLYGON ZM
+    3011: MultiCurve,  # MULTICURVE ZM
+    3012: MultiSurface,  # MULTISURFACE ZM
     1 + OGRGeomType.wkb25bit: Point,  # POINT Z
     2 + OGRGeomType.wkb25bit: LineString,  # LINESTRING Z
     3 + OGRGeomType.wkb25bit: Polygon,  # POLYGON Z
diff --git a/django/contrib/gis/gdal/prototypes/geom.py b/django/contrib/gis/gdal/prototypes/geom.py
index 25af48570b..9066dbd423 100644
--- a/django/contrib/gis/gdal/prototypes/geom.py
+++ b/django/contrib/gis/gdal/prototypes/geom.py
@@ -85,6 +85,13 @@ is_3d = bool_output(lgdal.OGR_G_Is3D, [c_void_p])
 set_3d = void_output(lgdal.OGR_G_Set3D, [c_void_p, c_int], errcheck=False)
 is_measured = bool_output(lgdal.OGR_G_IsMeasured, [c_void_p])
 set_measured = void_output(lgdal.OGR_G_SetMeasured, [c_void_p, c_int], errcheck=False)
+has_curve_geom = bool_output(lgdal.OGR_G_HasCurveGeometry, [c_void_p, c_int])
+get_linear_geom = geom_output(
+    lgdal.OGR_G_GetLinearGeometry, [c_void_p, c_double, POINTER(c_char_p)]
+)
+get_curve_geom = geom_output(
+    lgdal.OGR_G_GetCurveGeometry, [c_void_p, POINTER(c_char_p)]
+)
 
 # Geometry modification routines.
 add_geom = void_output(lgdal.OGR_G_AddGeometry, [c_void_p, c_void_p])
diff --git a/docs/ref/contrib/gis/gdal.txt b/docs/ref/contrib/gis/gdal.txt
index c2a333f895..726cd83756 100644
--- a/docs/ref/contrib/gis/gdal.txt
+++ b/docs/ref/contrib/gis/gdal.txt
@@ -611,6 +611,26 @@ coordinate transformation:
         >>> polygon.geom_count
         1
 
+    .. attribute:: has_curve
+
+    .. versionadded:: 5.2
+
+    A boolean indicating if this geometry is or contains a curve geometry.
+
+    .. method:: get_linear_geometry
+
+    .. versionadded:: 5.2
+
+    Returns a linear version of the geometry. If no conversion can be made, the
+    original geometry is returned.
+
+    .. method:: get_curve_geometry
+
+    .. versionadded:: 5.2
+
+    Returns a curved version of the geometry. If no conversion can be made, the
+    original geometry is returned.
+
     .. attribute:: point_count
 
     Returns the number of points used to describe this geometry:
diff --git a/docs/releases/5.2.txt b/docs/releases/5.2.txt
index 9090f8b70a..507676d998 100644
--- a/docs/releases/5.2.txt
+++ b/docs/releases/5.2.txt
@@ -94,7 +94,11 @@ Minor features
 :mod:`django.contrib.gis`
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
-* ...
+* GDAL now supports curved geometries ``CurvePolygon``, ``CompoundCurve``,
+  ``CircularString``, ``MultiSurface``, and ``MultiCurve`` via the new
+  :attr:`.OGRGeometry.has_curve` property, and the
+  :meth:`.OGRGeometry.get_linear_geometry` and
+  :meth:`.OGRGeometry.get_curve_geometry` methods.
 
 :mod:`django.contrib.messages`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/tests/gis_tests/data/geometries.json b/tests/gis_tests/data/geometries.json
index 7786f26e9b..eb6c64b6d9 100644
--- a/tests/gis_tests/data/geometries.json
+++ b/tests/gis_tests/data/geometries.json
@@ -137,5 +137,87 @@
   "union_geoms": [
       {"wkt": "POLYGON ((-5 0,-5 10,5 10,5 5,10 5,10 -5,0 -5,0 0,-5 0))"},
       {"wkt": "POLYGON ((2 0, 2 15, 18 15, 18 0, 2 0))"}
+  ],
+"curved_geoms": [
+    {"wkt": "CIRCULARSTRING(1 5, 6 2, 7 3)",
+     "name": "CircularString",
+     "num": 8
+    },
+    {"wkt": "COMPOUNDCURVE((5 3, 5 13), CIRCULARSTRING(5 13, 7 15, 9 13), (9 13, 9 3), CIRCULARSTRING(9 3, 7 1, 5 3))",
+     "name": "CompoundCurve",
+     "num": 9
+    },
+    {"wkt": "CURVEPOLYGON(CIRCULARSTRING(0 0, 4 0, 4 4, 0 4, 0 0),(1 1, 3 3, 3 1, 1 1))",
+     "name": "CurvePolygon",
+     "num": 10
+    },
+    {"wkt": "MULTICURVE((0 0, 5 5), CIRCULARSTRING(4 0, 4 4, 8 4))",
+     "name": "MultiCurve",
+     "num": 11
+    },
+    {"wkt": "MULTISURFACE(((0 0, 0 1, 1 1, 1 0, 0 0)), ((1 1, 1 2, 2 2, 2 1, 1 1)))",
+     "name": "MultiSurface",
+     "num": 12
+    },
+    {"wkt": "CIRCULARSTRING Z (1 5 1, 6 2 2, 7 3 3)",
+     "name": "CircularStringZ",
+     "num": 1008
+    },
+    {"wkt": "COMPOUNDCURVE Z ((5 3 0, 5 13 0), CIRCULARSTRING Z (5 13 0, 7 15 0, 9 13 0), (9 13 0 , 9 3 0), CIRCULARSTRING(9 3 0, 7 1 0, 5 3 0))",
+     "name": "CompoundCurveZ",
+     "num": 1009
+    },
+    {"wkt": "CURVEPOLYGON Z(CIRCULARSTRING Z (0 0 0, 4 0 0, 4 4 0, 0 4 0, 0 0 0),(1 1 0, 3 3 0, 3 1 0, 1 1 0))",
+     "name": "CurvePolygonZ",
+     "num": 1010
+    },
+    {"wkt": "MULTICURVE Z ((0 0 1, 5 5 2), CIRCULARSTRING Z (4 0 0, 4 4 0, 8 4 0))",
+     "name": "MultiCurveZ",
+     "num": 1011
+    },
+    {"wkt": "MULTISURFACE Z (((0 0 1, 0 1 2, 1 1 3, 1 0 4, 0 0 5)), ((1 1 0, 1 2 0, 2 2 0, 2 1 0, 1 1 0)))",
+     "name": "MultiSurfaceZ",
+     "num": 1012
+    },
+    {"wkt": "CIRCULARSTRING M (1 5 1, 6 2 2, 7 3 3)",
+     "name": "CircularStringM",
+     "num": 2008
+    },
+    {"wkt": "COMPOUNDCURVE M ((5 3 0, 5 13 0), CIRCULARSTRING M (5 13 0, 7 15 0, 9 13 0), (9 13 0 , 9 3 0), CIRCULARSTRING M (9 3 0, 7 1 0, 5 3 0))",
+     "name": "CompoundCurveM",
+     "num": 2009
+    },
+    {"wkt": "CURVEPOLYGON M (CIRCULARSTRING M (0 0 0, 4 0 0, 4 4 0, 0 4 0, 0 0 0),(1 1 0, 3 3 1, 3 1 1, 1 1 2))",
+     "name": "CurvePolygonM",
+     "num": 2010
+    },
+    {"wkt": "MULTICURVE M ((0 0 1, 5 5 2), CIRCULARSTRING M (4 0 0, 4 4 0, 8 4 0))",
+     "name": "MultiCurveM",
+     "num": 2011
+    },
+    {"wkt": "MULTISURFACE M (((0 0 1, 0 1 2, 1 1 3, 1 0 4, 0 0 5)), ((1 1 0, 1 2 0, 2 2 0, 2 1 0, 1 1 0)))",
+     "name": "MultiSurfaceM",
+     "num": 2012
+    },
+    {"wkt": "CIRCULARSTRING ZM (1 5 0 1, 6 2 0 2, 7 3 0 3)",
+     "name": "CircularStringZM",
+     "num": 3008
+    },
+    {"wkt": "COMPOUNDCURVE ZM ((5 3 0 0, 5 13 0 0), CIRCULARSTRING ZM (5 13 0 0, 7 15 0 0, 9 13 0 0), (9 13 0 0, 9 3 0 0), CIRCULARSTRING ZM (9 3 0 0, 7 1 0 0, 5 3 0 0))",
+     "name": "CompoundCurveZM",
+     "num": 3009
+    },
+    {"wkt": "CURVEPOLYGON ZM (CIRCULARSTRING ZM (0 0 0 0, 4 0 0 0, 4 4 0 0, 0 4 0 0, 0 0 0 0), (1 1 0 0, 3 3 0 0, 3 1 0 0, 1 1 0 0))",
+     "name": "CurvePolygonZM",
+     "num": 3010
+    },
+    {"wkt": "MULTICURVE ZM ((0 0 0 1, 5 5 0 2), CIRCULARSTRING ZM (4 0 0 0, 4 4 0 0, 8 4 0 0))",
+     "name": "MultiCurveZM",
+     "num": 3011
+    },
+    {"wkt": "MULTISURFACE ZM (((0 0 0 1, 0 1 0 2, 1 1 0 3, 1 0 0 4, 0 0 0 5)), ((1 1 0 0, 1 2 0 0, 2 2 0 0, 2 1 0 0, 1 1 0 0)))",
+     "name": "MultiSurfaceZM",
+     "num": 3012
+    }
   ]
 }
diff --git a/tests/gis_tests/gdal_tests/test_geom.py b/tests/gis_tests/gdal_tests/test_geom.py
index 5c23a6f2cf..6c551d0804 100644
--- a/tests/gis_tests/gdal_tests/test_geom.py
+++ b/tests/gis_tests/gdal_tests/test_geom.py
@@ -8,6 +8,8 @@ from django.contrib.gis.gdal import (
     OGRGeomType,
     SpatialReference,
 )
+from django.contrib.gis.gdal.geometries import CircularString, CurvePolygon
+from django.contrib.gis.geos import GEOSException
 from django.template import Context
 from django.template.engine import Engine
 from django.test import SimpleTestCase
@@ -646,11 +648,11 @@ class OGRGeomTest(SimpleTestCase, TestDataMixin):
             ("Multilinestring", 5, True),
             ("MultiPolygon", 6, True),
             ("GeometryCollection", 7, True),
-            ("CircularString", 8, False),
-            ("CompoundCurve", 9, False),
-            ("CurvePolygon", 10, False),
-            ("MultiCurve", 11, False),
-            ("MultiSurface", 12, False),
+            ("CircularString", 8, True),
+            ("CompoundCurve", 9, True),
+            ("CurvePolygon", 10, True),
+            ("MultiCurve", 11, True),
+            ("MultiSurface", 12, True),
             # 13 (Curve) and 14 (Surface) are abstract types.
             ("PolyhedralSurface", 15, False),
             ("TIN", 16, False),
@@ -664,11 +666,11 @@ class OGRGeomTest(SimpleTestCase, TestDataMixin):
             ("Multilinestring Z", -2147483643, True),  # 1005
             ("MultiPolygon Z", -2147483642, True),  # 1006
             ("GeometryCollection Z", -2147483641, True),  # 1007
-            ("CircularString Z", 1008, False),
-            ("CompoundCurve Z", 1009, False),
-            ("CurvePolygon Z", 1010, False),
-            ("MultiCurve Z", 1011, False),
-            ("MultiSurface Z", 1012, False),
+            ("CircularString Z", 1008, True),
+            ("CompoundCurve Z", 1009, True),
+            ("CurvePolygon Z", 1010, True),
+            ("MultiCurve Z", 1011, True),
+            ("MultiSurface Z", 1012, True),
             ("PolyhedralSurface Z", 1015, False),
             ("TIN Z", 1016, False),
             ("Triangle Z", 1017, False),
@@ -679,11 +681,11 @@ class OGRGeomTest(SimpleTestCase, TestDataMixin):
             ("MultiLineString M", 2005, True),
             ("MultiPolygon M", 2006, True),
             ("GeometryCollection M", 2007, True),
-            ("CircularString M", 2008, False),
-            ("CompoundCurve M", 2009, False),
-            ("CurvePolygon M", 2010, False),
-            ("MultiCurve M", 2011, False),
-            ("MultiSurface M", 2012, False),
+            ("CircularString M", 2008, True),
+            ("CompoundCurve M", 2009, True),
+            ("CurvePolygon M", 2010, True),
+            ("MultiCurve M", 2011, True),
+            ("MultiSurface M", 2012, True),
             ("PolyhedralSurface M", 2015, False),
             ("TIN M", 2016, False),
             ("Triangle M", 2017, False),
@@ -694,11 +696,11 @@ class OGRGeomTest(SimpleTestCase, TestDataMixin):
             ("MultiLineString ZM", 3005, True),
             ("MultiPolygon ZM", 3006, True),
             ("GeometryCollection ZM", 3007, True),
-            ("CircularString ZM", 3008, False),
-            ("CompoundCurve ZM", 3009, False),
-            ("CurvePolygon ZM", 3010, False),
-            ("MultiCurve ZM", 3011, False),
-            ("MultiSurface ZM", 3012, False),
+            ("CircularString ZM", 3008, True),
+            ("CompoundCurve ZM", 3009, True),
+            ("CurvePolygon ZM", 3010, True),
+            ("MultiCurve ZM", 3011, True),
+            ("MultiSurface ZM", 3012, True),
             ("PolyhedralSurface ZM", 3015, False),
             ("TIN ZM", 3016, False),
             ("Triangle ZM", 3017, False),
@@ -967,6 +969,101 @@ class OGRGeomTest(SimpleTestCase, TestDataMixin):
                 geom = OGRGeometry(geom_input)
                 self.assertIs(geom.is_measured, True)
 
+    def test_has_curve(self):
+        for geom in self.geometries.curved_geoms:
+            with self.subTest(wkt=geom.wkt):
+                geom = OGRGeometry(geom.wkt)
+                self.assertIs(geom.has_curve, True)
+                msg = f"GEOS does not support {geom.__class__.__qualname__}."
+                with self.assertRaisesMessage(GEOSException, msg):
+                    geom.geos
+        geom = OGRGeometry("POINT (0 1)")
+        self.assertIs(geom.has_curve, False)
+
+    def test_get_linear_geometry(self):
+        geom = OGRGeometry("CIRCULARSTRING (-0.797 0.466,-0.481 0.62,-0.419 0.473)")
+        linear = geom.get_linear_geometry()
+        self.assertEqual(linear.geom_name, "LINESTRING")
+        self.assertIs(linear.has_curve, False)
+
+    def test_get_linear_geometry_no_conversion_possible(self):
+        wkt = "POINT (0 0)"
+        geom = OGRGeometry(wkt)
+        geom2 = geom.get_linear_geometry()
+        self.assertEqual(geom2.wkt, wkt)
+
+    def test_get_curve_geometry(self):
+        linear_string = OGRGeometry(
+            "LINESTRING (-0.797 0.466,-0.797500910583869 0.479079607685707,"
+            "-0.797096828208069 0.49216256476959,-0.795789684575482 0.505186328593822,"
+            "-0.793585728444384 0.518088639471983,-0.79049549575663 0.530807818319715,"
+            "-0.786533759270668 0.543283061509385,-0.781719457941079 0.555454731539925,"
+            "-0.776075606381369 0.567264642132187,-0.769629184843353 0.578656336386302,"
+            "-0.76241101023902 0.589575356672327,-0.754455588821145 0.599969504963013,"
+            "-0.745800951227352 0.609789092364991,-0.736488470675795 0.618987176654798,"
+            "-0.726562665181888 0.627519786684672,-0.716070984741265 0.635346132585369,"
+            "-0.705063584496685 0.642428800760598,-0.693593084972889 0.648733932741749,"
+            "-0.681714320525941 0.654231387047048,-0.669484077209319 0.658894883272069,"
+            "-0.656960821309923 0.662702127722269,-0.644204419852031 0.665634919987354,"
+            "-0.631275854404748 0.667679239947688,-0.618236929561618 0.668825314797118,"
+            "-0.60514997748578 0.669067665761503,-0.592077559933017 0.66840513428977,"
+            "-0.579082169177269 0.666840887592428,-0.566225929268313 0.664382403500809,"
+            "-0.553570299049824 0.661041434719465,-0.541175778357228 0.656833952642756,"
+            "-0.529101618800212 0.651780071004197,-0.5174055405123 0.645903949723276,"
+            "-0.506143456221622 0.639233679409784,-0.495369203961872 0.631801147077652,"
+            "-0.485134289701335 0.623641883709865,-0.475487641120239 0.614794894404014,"
+            "-0.46647537371355 0.605302471909454,-0.458140570337321 0.595209994448282,"
+            "-0.450523075252448 0.58456570878613,-0.443659303650563 0.573420499590156,"
+            "-0.437582067572208 0.561827646176397,-0.432320419050072 0.549842567809747,"
+            "-0.427899511226613 0.537522558773986,-0.424340478110267 0.524926514478182,"
+            "-0.421660333544978 0.512114649909193,-0.419871889876113 0.499148211775737,"
+            "-0.418983696701434 0.486089185720561,-0.419 0.473)"
+        )
+        curve = linear_string.get_curve_geometry()
+        self.assertEqual(curve.geom_name, "CIRCULARSTRING")
+        self.assertEqual(
+            curve.wkt,
+            "CIRCULARSTRING (-0.797 0.466,-0.618236929561618 "
+            "0.668825314797118,-0.419 0.473)",
+        )
+
+    def test_get_curve_geometry_no_conversion_possible(self):
+        geom = OGRGeometry("LINESTRING (0 0, 1 0, 2 0)")
+        geom2 = geom.get_curve_geometry()
+        self.assertEqual(geom2.wkt, geom.wkt)
+
+    def test_curved_geometries(self):
+        for geom in self.geometries.curved_geoms:
+            with self.subTest(wkt=geom.wkt, geom_name=geom.name):
+                g = OGRGeometry(geom.wkt)
+                self.assertEqual(geom.name, g.geom_type.name)
+                self.assertEqual(geom.num, g.geom_type.num)
+                msg = f"GEOS does not support {g.__class__.__qualname__}."
+                with self.assertRaisesMessage(GEOSException, msg):
+                    g.geos
+
+    def test_circularstring_has_linestring_features(self):
+        geom = OGRGeometry("CIRCULARSTRING ZM (1 5 0 1, 6 2 0 2, 7 3 0 3)")
+        self.assertIsInstance(geom, CircularString)
+        self.assertEqual(geom.x, [1, 6, 7])
+        self.assertEqual(geom.y, [5, 2, 3])
+        self.assertEqual(geom.z, [0, 0, 0])
+        self.assertEqual(geom.m, [1, 2, 3])
+        self.assertEqual(
+            geom.tuple,
+            ((1.0, 5.0, 0.0, 1.0), (6.0, 2.0, 0.0, 2.0), (7.0, 3.0, 0.0, 3.0)),
+        )
+        self.assertEqual(geom[0], (1, 5, 0, 1))
+        self.assertEqual(len(geom), 3)
+
+    def test_curvepolygon_has_polygon_features(self):
+        geom = OGRGeometry(
+            "CURVEPOLYGON ZM (CIRCULARSTRING ZM (0 0 0 0, 4 0 0 0, 4 4 0 0, 0 4 0 0, "
+            "0 0 0 0), (1 1 0 0, 3 3 0 0, 3 1 0 0, 1 1 0 0))"
+        )
+        self.assertIsInstance(geom, CurvePolygon)
+        self.assertIsInstance(geom.shell, CircularString)
+
 
 class DeprecationTests(SimpleTestCase):
     def test_coord_setter_deprecation(self):