Add PyOsmium dependency and implement OSM writing

- Currently, there is no determination of stop sign kind. So it's unclear whether it is for busses, trams, ferries, etc...

zhv_parser/ZHV_Converter.py

+import os
 import sys
-from io import StringIO
+from datetime import date
+from enum import Enum
+from typing import Sequence
 
+import osmium
 from lxml import etree
+from osmium.osm import create_mutable_relation, create_mutable_node
+from osmium.osm import Location
+from osmium.osm._osm import RelationMember
+from osmium.osm.mutable import Relation, Node
 
 from zhv_parser import ZHV_Classes
 from zhv_parser.RegionCode import RegionCode
 from zhv_parser.ZHV_Classes import StopPlace, Area, Quay, Name
 
+# ZHV related XML tags, elements
 namespace: str = "{http://zhv.xml.wvi/}"
 tag_stop_place: str = namespace + "StopPlace"
 tag_area: str = namespace + "Area"
@@ -15,67 +24,183 @@ tag_quay: str = namespace + "Quay"
 event_start: str = "start"
 event_end: str = "end"
 
-
-def parse(xml_file):
-    context = etree.iterparse(xml_file, events=(event_start, event_end),
-                              tag=(tag_stop_place, tag_area, tag_quay))
-    # TODO: Übergebe context (iterator) an nächste Stufe zur Extraktion der Daten
-    for action, elem in context:
-        if elem.tag == tag_stop_place and action == event_start:
-            stop_place_class = ZHV_Classes.StopPlace
-            stop_place = stop_place_class.factory()
-            stop_place.build(elem)
-            if is_stop_place_in_region(RegionCode.BRANDENBURG, stop_place):
-                print(stop_place)
-                stop_place_to_osm(stop_place, context)
-            else:
-                print("Not in Region!")
-
-
-def is_stop_place_in_region(region_code: RegionCode, stop_place: StopPlace):
-    return region_code.isStopPlaceInRegion(stop_place)
-
-
-def stop_place_to_osm(stop_place: StopPlace, context):
-    """Converts stop place to an OSM object """
-    # extract stop place parameters
-    # TODO: Ask ZHV: Why are names double encapsulated?
-    stop_place_name: str = stop_place.get_Name().get_Name()[0].get_valueOf_()
-
-    for action, elem in context:
-        if elem.tag == tag_area and action == event_start:
-            area_class = ZHV_Classes.Area
-            area = area_class.factory()
-            area.build(elem)
-            area_to_osm(area, context)
-
-        elif elem.tag == tag_stop_place and action == event_end:
-            return
-
-
-def area_to_osm(area: Area, context):
-    # extract area parameters
-    for action, elem in context:
-        if elem.tag == tag_quay and action == event_start:
-            quay_class = ZHV_Classes.Quay
-            quay = quay_class.factory()
-            quay.build(elem)
-            quay_to_osm(quay, context)
-        elif elem.tag == tag_area and action == event_end:
-            return
-
-
-def quay_to_osm(quay: Quay, context):
-    # extract quay parameters
-    # TODO: Ask ZHV: Why are names double encapsulated?
-    quay_name: str = quay.get_Name().get_Name()[0].get_valueOf_()
-    quay_dhid: str = quay.get_DHID()
-    quay_lat: str = quay.get_Location().get_Latitude()
-    quay_lon: str = quay.get_Location().get_Longitude()
-    # return to previous structure hierarchy
-    for action, elem in context:
-        if elem.tag == tag_quay and action == event_end:
-            return
+# OSM related PT tags: https://wiki.openstreetmap.org/wiki/DE:Public_transport
+# General tags:
+osm_tag_name = ('name', '')  # example: name=TU Campus -> used in relation
+# -> for search machines -> used at the stop position
+osm_tag_ref = ('ref', '')  # example: ref=TU Campus, Bstg. 3A -> used at the stop platform or stop sign
+osm_tag_ref_ifopt = ('ref:IFOPT', '')
+
+
+# OSM Tags for stop place (relation): also use OSM tag "name=*"
+osm_tag_type_pt = ('type', 'public_transport')
+osm_tag_stop_place = ('public_transport', 'stop_area')
+osm_tag_ref_name = ('ref_name', '')  # example: ref_name=TU Campus, Chemnitz
+osm_relation_role_platform = 'platform'
+osm_relation_type_node = 'node'
+# <member type='node' ref='node_id' role='platform' />
+# example:
+# <relation id='7795887' timestamp='2019-08-25T21:04:46Z' uid='559480' user='SvenQ' visible='true' version='4' changeset='73726675'>
+#     <member type='node' ref='5274416450' role='stop' />
+#     <member type='way' ref='545750504' role='platform' />
+#     <member type='node' ref='5272770752' role='stop' />
+#     <member type='way' ref='545750513' role='platform' />
+#     <member type='node' ref='5272770751' role='stop' />
+#     <member type='way' ref='545750516' role='platform' />
+#     <member type='node' ref='5272770754' role='stop' />
+#     <member type='way' ref='545750519' role='platform' />
+#     <member type='node' ref='5272770753' role='stop' />
+#     <member type='way' ref='545750520' role='platform' />
+#     <member type='node' ref='5239435218' role='stop' />
+#     <member type='way' ref='545750524' role='platform' />
+#     <tag k='fare_zone' v='13' />
+#     <tag k='name' v='TU Campus' />
+#     <tag k='network' v='Verkehrsverbund Mittelsachsen' />
+#     <tag k='operator' v='Chemnitzer Verkehrs-AG' />
+#     <tag k='public_transport' v='stop_area' />
+#     <tag k='ref_name' v='TU Campus, Chemnitz' />
+#     <tag k='type' v='public_transport' />
+#   </relation>
+
+
+# OSM tags for stop positions of buses and trams
+osm_tag_stop_position = ('public_transport', 'stop_position')
+osm_tag_bus = ('bus', 'yes')
+osm_tag_tram = ('tram', 'yes')
+osm_tag_tram_stop = ('railway', 'tram_stop')
+
+# for platforms or stop signs (https://wiki.openstreetmap.org/wiki/Tag:public_transport%3Dplatform)
+osm_tag_platform_pt = ('public_transport', 'platform')  # for nodes and ways
+osm_tag_platform_railway = ('railway', 'platform')  # for nodes and ways that define tram/rail platforms
+osm_tag_highway_bus_stop_sign = ('highway', 'bus_stop')  # for nodes that define stop sign positions
+#osm_tag_highway_bus_platform = ('highway', 'platform')  # for ways that define bus platform areas or lines
+# -> ZHV contains only nodes/points, therefore not necessary
+osm_tag_fixme_type_unknown = ('fixme', 'Ist diese Haltestelle für Straßenbahnen, Busse oder etwas ganz anderes?')
+
+# For trams: https://wiki.openstreetmap.org/wiki/Tag:railway%3Dtram_stop
+
+
+class StopSignType(Enum):
+    BUS = osm_tag_highway_bus_stop_sign
+    TRAM = osm_tag_platform_railway
+    UNKNOWN = osm_tag_fixme_type_unknown
+
+class ZhvConverter:
+
+    def __init__(self):
+        self.unused_osm_id = 0
+
+    def parse(self, xml_file):
+        today = date.today()
+        # dd/mm/YY
+        d1 = today.strftime("%Y-%m-%d-")
+        file_name = d1 + 'stop_places.osm'
+        if os.path.exists(file_name):
+            os.remove(file_name)
+
+        writer = osmium.SimpleWriter(file_name)
+        context = etree.iterparse(xml_file, events=(event_start, event_end),
+                                  tag=(tag_stop_place, tag_area, tag_quay))
+        for action, elem in context:
+            if elem.tag == tag_stop_place and action == event_start:
+                stop_place_class = ZHV_Classes.StopPlace
+                stop_place = stop_place_class.factory()
+                stop_place.build(elem)
+                if not self.is_stop_place_in_region(RegionCode.BRANDENBURG, stop_place):
+                    continue
+
+                (stop_place_relation, nodes) = self.stop_place_to_osm(stop_place, context)
+                if stop_place_relation is not None:
+                    for node in nodes:
+                        writer.add_node(node)
+                    writer.add_relation(stop_place_relation)
+
+        writer.close()
+
+    def is_stop_place_in_region(self, region_code: RegionCode, stop_place: StopPlace):
+        return region_code.isStopPlaceInRegion(stop_place)
+
+    def stop_place_to_osm(self, stop_place: StopPlace, context) -> (Relation, Sequence[Node]):
+        """Converts stop place to an OSM object"""
+        # extract stop place parameters
+        # TODO: Ask ZHV: Why are names double encapsulated?
+        stop_place_name: str = stop_place.get_Name().get_Name()[0].get_valueOf_()
+        # create relation:
+        stop_place_relation: Relation = Relation()
+        stop_place_relation.members = list()
+        stop_place_relation.tags = list(tuple())
+        stop_place_relation.tags.append(tuple([osm_tag_ref_name[0], stop_place_name]))
+        stop_place_relation.tags.append(osm_tag_type_pt)
+        stop_place_relation.tags.append(osm_tag_stop_place)
+        stop_place_relation.id = self.get_unused_osm_id()
+
+        list_stop_signs = list()
+        for action, elem in context:
+            if elem.tag == tag_area and action == event_start:
+                area_class = ZHV_Classes.Area
+                area = area_class.factory()
+                area.build(elem)
+                list_stop_signs += self.area_to_osm(area, context)
+
+            elif elem.tag == tag_stop_place and action == event_end:
+                if len(list_stop_signs) == 0:
+                    return None
+                else:
+                    # todo assign IDs of stop signs as members to stop place relation
+                    for stop_sign in list_stop_signs:
+                        stop_place_relation.members.append(tuple([osm_relation_type_node, stop_sign.id, osm_relation_role_platform]))
+
+                    return stop_place_relation, list_stop_signs
+
+    def area_to_osm(self, area: Area, context) -> Sequence[Node]:
+        list_nodes = list()
+        # extract type of stop sign (Bus, Tram, etc.?) -> unfortunately, there is no standard attribute for this
+        # One possible criteria for bus/tram distinguishing: (used by HannIT)
+        #             <Description>
+        #               <Description>Bus</Description>
+        #             </Description>
+        # 2nd possible criteria:
+        #  <Name>
+        #    <Name>Tram</Name> or <Name>Bus</Name>
+        #  </Name>
+
+        # name = area.get_Name().get_Name()[0].get_valueOf_()
+        # description = area.get_
+        stop_sign_type = StopSignType.UNKNOWN
+
+        for action, elem in context:
+            if elem.tag == tag_quay and action == event_start:
+                quay_class = ZHV_Classes.Quay
+                quay = quay_class.factory()
+                quay.build(elem)
+                list_nodes.append(self.quay_to_osm(quay, stop_sign_type, context))
+            elif elem.tag == tag_area and action == event_end:
+                return list_nodes
+
+    def quay_to_osm(self, quay: Quay, stop_sign_type: StopSignType , context) -> Node:
+        """ Extract an OSM node from the given ZHV stop sign structure """
+        # extract quay parameters
+        # TODO: Ask ZHV: Why are names double encapsulated?
+        quay_name: str = quay.get_Name().get_Name()[0].get_valueOf_()
+        quay_dhid: str = quay.get_DHID()
+        quay_lat: str = quay.get_Location().get_Latitude()
+        quay_lon: str = quay.get_Location().get_Longitude()
+        node_stop_sign: Node = Node()
+        node_stop_sign.id = self.get_unused_osm_id()
+        node_stop_sign.location = Location(quay_lon, quay_lat)
+        node_stop_sign.tags = list()
+        node_stop_sign.tags.append((osm_tag_ref_ifopt[0], quay_dhid))
+        node_stop_sign.tags.append(osm_tag_platform_pt)
+        node_stop_sign.tags.append(stop_sign_type.value)
+
+        # return to previous structure hierarchy
+        for action, elem in context:
+            if elem.tag == tag_quay and action == event_end:
+                return node_stop_sign
+
+    def get_unused_osm_id(self):
+        self.unused_osm_id -= 1
+        return self.unused_osm_id
 
 
 USAGE_TEXT = """
@@ -93,7 +218,8 @@ def main():
     if len(args) != 1:
         usage()
     infile_name = args[0]
-    parse(infile_name)
+    ZhvConverter().parse(infile_name)
+
 
 if __name__ == '__main__':
     main()