Use shapely.LineString in abstract Line class

openlr_dereferencer/example_sqlite_map/primitives.py

@@ -3,6 +3,7 @@
 from itertools import chain
 from typing import Iterable
 from openlr import Coordinates, FRC, FOW
+from shapely.geometry import LineString
 from ..maps import Line as AbstractLine, Node as AbstractNode
 
 # https://epsg.io/4326
@@ -54,11 +55,11 @@ def frc(self) -> FRC:
         (frc,) = self.map_reader.connection.execute(stmt, (self.line_id,)).fetchone()
         return FRC(frc)
 
-    def coordinates(self) -> Iterable[Coordinates]:
-        "Yields every point in the path geometry as Coordinates"
-        for index in range(self.num_points()):
-            lon, lat = self.point_n(index + 1)
-            yield Coordinates(lon=lon, lat=lat)
+    @property
+    def shape(self) -> LineString:
+        "Returns the line geometry"
+        points = [self.point_n(index + 1) for index in range(self.num_points())]
+        return LineString(points)
 
     def distance_to(self, coord) -> float:
         "Returns the distance of this line to `coord` in meters"

openlr_dereferencer/maps/abstract.py

@@ -1,9 +1,9 @@
 """An abstract `MapReader` base class, which must be implemented for each
 map format to decode location references on."""
 from abc import ABC, abstractmethod
-from typing import Iterable, Hashable
+from typing import Iterable, Hashable, Sequence
 from openlr import Coordinates, FOW, FRC
-
+from shapely.geometry import LineString
 
 class Line(ABC):
     "Abstract Line class, modelling a line coming from a map reader"
@@ -33,10 +33,14 @@ def frc(self) -> FRC:
     def fow(self) -> FOW:
         "Returns the form of way of this line"
 
+    @property
     @abstractmethod
-    def coordinates(self) -> Iterable[Coordinates]:
-        """Returns the shape of the line.
-        Yields GeoCoordinate values."""
+    def shape(self) -> LineString:
+        "Returns the geometric shape as a linestring"
+
+    def coordinates(self) -> Sequence[Coordinates]:
+        """Returns the shape of the line as list of Coordinates"""
+        return [Coordinates(*point) for point in self.shape.coords]
 
     @property
     def length(self) -> float:

setup.py

@@ -23,7 +23,7 @@
         'openlr_dereferencer.maps.a_star',
         'openlr_dereferencer.decoding',
         'openlr_dereferencer'],
-    install_requires=["openlr", "geographiclib"],
+    install_requires=["openlr", "geographiclib", "shapely"],
     test_suite="tests",
     python_requires=">=3.6",
     classifiers=[