Example for converting Overpass response to shapely geometry

examples/overpass_geometry.py

@@ -0,0 +1,60 @@
+"""
+Download example object from Overpass and turn it to shapely geometry and analyze shapely geometries
+"""
+import requests
+import shapely.ops
+import shapely.wkb
+
+import osmium as o
+
+wkb_factory = o.geom.WKBFactory()
+
+
+class GeometryHandler(o.SimpleHandler):
+    def __init__(self):
+        super(GeometryHandler, self).__init__()
+        self.__geometries = []
+
+    def way(self, w):
+        if 'amenity' in w.tags:
+            wkb = wkb_factory.create_linestring(w)
+            shape = shapely.wkb.loads(wkb, hex=True)
+            self.__geometries.append(shape)
+
+    @property
+    def geometries(self):
+        return self.__geometries
+
+
+def get_geometries(data):
+    # use MergeInputReader to sort input, so nodes will come first. Otherwise invalid locations could be passed
+    # in ways/relations GeometryHandler
+    mir = o.MergeInputReader()
+    mir.add_buffer(data, "osm")  # Overpass returns data in osm format
+    gh = GeometryHandler()
+    # use memory index (flex_mem) for node locations cache. Use "sparse_file_array,<filename>" for file backed indices
+    mir.apply(gh, idx='flex_mem')
+    return gh.geometries
+
+
+def analyze(geoms):
+    """Union all geometries and get its centroid"""
+    print(shapely.ops.cascaded_union(geoms).centroid)
+
+
+def overpass_query():
+    resp = requests.post(url="https://overpass-api.de/api/interpreter",
+                         data="[timeout:30];"
+                              "way[amenity]"
+                              "(41.886272470886496,12.476906776428223,41.89371621291292,12.507097721099854);"
+                              "out body;"
+                              ">;"
+                              "out body;"
+                         )
+    if resp.ok:
+        return resp.content
+    raise RuntimeError("Invalid response from Overpass: " + resp.text)
+
+
+if __name__ == '__main__':
+    analyze(get_geometries(overpass_query()))