Refs #35058 -- Added support for measured geometries to GDAL LineString.

Author: smithdc1

django/contrib/gis/gdal/geometries.py

@@ -625,10 +625,14 @@ class LineString(OGRGeometry):
     def __getitem__(self, index):
         "Return the Point at the given index."
         if 0 <= index < self.point_count:
-            x, y, z = c_double(), c_double(), c_double()
-            capi.get_point(self.ptr, index, byref(x), byref(y), byref(z))
+            x, y, z, m = c_double(), c_double(), c_double(), c_double()
+            capi.get_point(self.ptr, index, byref(x), byref(y), byref(z), byref(m))
+            if self.is_3d and self.is_measured:
+                return x.value, y.value, z.value, m.value
             if self.is_3d:
                 return x.value, y.value, z.value
+            if self.is_measured:
+                return x.value, y.value, m.value
             dim = self.coord_dim
             if dim == 1:
                 return (x.value,)
@@ -673,6 +677,12 @@ def z(self):
         if self.is_3d:
             return self._listarr(capi.getz)
 
+    @property
+    def m(self):
+        """Return the M coordinates in a list."""
+        if self.is_measured:
+            return self._listarr(capi.getm)
+
 
 # LinearRings are used in Polygons.
 class LinearRing(LineString):
@@ -789,9 +799,11 @@ class MultiPolygon(GeometryCollection):
     7: GeometryCollection,
     101: LinearRing,
     2001: Point,  # POINT M
+    2002: LineString,  # LINESTRING M
     3001: Point,  # POINT ZM
+    3002: LineString,  # LINESTRING ZM
     1 + OGRGeomType.wkb25bit: Point,  # POINT Z
-    2 + OGRGeomType.wkb25bit: LineString,
+    2 + OGRGeomType.wkb25bit: LineString,  # LINESTRING Z
     3 + OGRGeomType.wkb25bit: Polygon,
     4 + OGRGeomType.wkb25bit: MultiPoint,
     5 + OGRGeomType.wkb25bit: MultiLineString,

django/contrib/gis/gdal/prototypes/geom.py

@@ -137,8 +137,15 @@ def topology_func(f):
 get_geom_type = int_output(lgdal.OGR_G_GetGeometryType, [c_void_p])
 get_point_count = int_output(lgdal.OGR_G_GetPointCount, [c_void_p])
 get_point = void_output(
-    lgdal.OGR_G_GetPoint,
-    [c_void_p, c_int, POINTER(c_double), POINTER(c_double), POINTER(c_double)],
+    lgdal.OGR_G_GetPointZM,
+    [
+        c_void_p,
+        c_int,
+        POINTER(c_double),
+        POINTER(c_double),
+        POINTER(c_double),
+        POINTER(c_double),
+    ],
     errcheck=False,
 )
 geom_close_rings = void_output(lgdal.OGR_G_CloseRings, [c_void_p], errcheck=False)

docs/ref/contrib/gis/gdal.txt

@@ -936,6 +936,17 @@ coordinate transformation:
         >>> OGRGeometry("LINESTRING (1 2 3,4 5 6)").z
         [3.0, 6.0]
 
+    .. attribute:: m
+
+    .. versionadded:: 5.1
+
+    Returns a list of M coordinates in this line or ``None`` if the line does
+    not have M coordinates:
+
+    .. code-block:: pycon
+
+        >>> OGRGeometry("LINESTRING(0 1 2 10, 1 2 3 11, 2 3 4 12)").m
+        [10.0, 11.0, 12.0]
 
 .. class:: Polygon
 

docs/releases/5.1.txt

@@ -78,10 +78,11 @@ Minor features
 * The new :meth:`.OGRGeometry.set_3d` method allows addition and removal of the
   ``Z`` coordinate dimension.
 
-* :class:`~django.contrib.gis.gdal.OGRGeometry` and
-  :class:`~django.contrib.gis.gdal.Point` now support measured geometries
-  via the new :attr:`.OGRGeometry.is_measured` and :attr:`.Point.m` properties,
-  and the :meth:`.OGRGeometry.set_measured` method.
+* :class:`~django.contrib.gis.gdal.OGRGeometry`,
+  :class:`~django.contrib.gis.gdal.Point`, and
+  :class:`~django.contrib.gis.gdal.LineString` now support measured geometries
+  via the new :attr:`.OGRGeometry.is_measured` and ``m`` properties, and the
+  :meth:`.OGRGeometry.set_measured` method.
 
 * :attr:`.OGRGeometry.centroid` is now available on all supported geometry
   types.

tests/gis_tests/gdal_tests/test_geom.py

@@ -673,7 +673,7 @@ def test_geometry_types(self):
             ("TIN Z", 1016, False),
             ("Triangle Z", 1017, False),
             ("Point M", 2001, True),
-            ("LineString M", 2002, False),
+            ("LineString M", 2002, True),
             ("Polygon M", 2003, False),
             ("MultiPoint M", 2004, False),
             ("MultiLineString M", 2005, False),
@@ -688,7 +688,7 @@ def test_geometry_types(self):
             ("TIN M", 2016, False),
             ("Triangle M", 2017, False),
             ("Point ZM", 3001, True),
-            ("LineString ZM", 3002, False),
+            ("LineString ZM", 3002, True),
             ("Polygon ZM", 3003, False),
             ("MultiPoint ZM", 3004, False),
             ("MultiLineString ZM", 3005, False),
@@ -900,6 +900,21 @@ def test_centroid(self):
         )
         self.assertEqual(geometrycollection.centroid.wkt, "POINT (110 30)")
 
+    def test_linestring_m_dimension(self):
+        geom = OGRGeometry("LINESTRING(0 1 2 10, 1 2 3 11, 2 3 4 12)")
+        self.assertIs(geom.is_measured, True)
+        self.assertEqual(geom.m, [10.0, 11.0, 12.0])
+        self.assertEqual(geom[0], (0.0, 1.0, 2.0, 10.0))
+
+        geom = OGRGeometry("LINESTRING M (0 1 10, 1 2 11)")
+        self.assertIs(geom.is_measured, True)
+        self.assertEqual(geom.m, [10.0, 11.0])
+        self.assertEqual(geom[0], (0.0, 1.0, 10.0))
+
+        geom.set_measured(False)
+        self.assertIs(geom.is_measured, False)
+        self.assertIs(geom.m, None)
+
 
 class DeprecationTests(SimpleTestCase):
     def test_coord_setter_deprecation(self):