add geo interface example

examples/geo_interface.py

@@ -0,0 +1,35 @@
+from shapely.geometry import shape
+from osmdiff.osm import Node, Way, Relation
+
+# Create a node with coordinates
+node = Node()
+node.attribs = {"lon": "-122.4", "lat": "37.7"}
+
+# Convert to Shapely Point using geo_interface
+point = shape(node.__geo_interface__)
+print(f"Node as Point: {point}")  # POINT (-122.4 37.7)
+
+# Create a way with nodes
+way = Way()
+way.nodes = [
+    Node(attribs={"lon": "-122.4", "lat": "37.7"}),
+    Node(attribs={"lon": "-122.4", "lat": "37.8"}),
+    Node(attribs={"lon": "-122.5", "lat": "37.8"}),
+    Node(attribs={"lon": "-122.4", "lat": "37.7"}),  # Closing the loop
+]
+
+# Convert to Shapely Polygon using geo_interface
+polygon = shape(way.__geo_interface__)
+print(
+    f"Way as Polygon: {polygon}"
+)  # POLYGON ((-122.4 37.7, -122.4 37.8, -122.5 37.8, -122.4 37.7))
+
+# Create a relation with members
+relation = Relation()
+relation.members = [way, node]
+
+# Convert to Shapely GeometryCollection using geo_interface
+collection = shape(relation.__geo_interface__)
+print(
+    f"Relation as Collection: {collection}"
+)  # GEOMETRYCOLLECTION (POLYGON ((-122.4 37.7, -122.4 37.8, -122.5 37.8, -122.4 37.7)), POINT (-122.4 37.7))