OSM reader.

osm_reader.py

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+"""
+Reading OpenStreetMap data from XML file.
+
+Author: Sergey Vartanov
+"""
+
+
+def parse_node_full(text):
+    """
+    Parse full node parameters using regular expressions: id, visible, version, 
+    etc. For faster parsing use parse_node().
+    """
+    m = re.match('id="(.*)" visible="(.*)" version="(.*)" changeset="(.*)" timestamp="(.*)" user="(.*)" uid="(.*)" lat="(.*)" lon="(.*)"', text)
+    if m:
+        return {'id': m.group(1), 'visible': m.group(2), 'changeset': m.group(3), 'timestamp': m.group(4), 'user': m.group(5), 'uid': m.group(6), 'lat': m.group(7), 'lon': m.group(8)}
+    else:
+        print 'Error node'
+
+def parse_node(text):
+    """
+    Parse just identifier, latitude, and longitude from node parameters.
+    """
+    id = text[4:text.find('"', 6)]
+    lat_index = text.find('lat')
+    lon_index = text.find('lon')
+    lat = text[lat_index + 5:text.find('"', lat_index + 7)]
+    lon = text[lon_index + 5:text.find('"', lon_index + 7)]
+    return {'id': id, 'lat': lat, 'lon': lon}
+
+def parse_way_full(text):
+    m = re.match('id="(.*)" visible="(.*)" version="(.*)" changeset="(.*)" timestamp="(.*)" user="(.*)" uid="(.*)"', text)
+    if m:
+        return {'id': m.group(1), 'visible': m.group(2), 'changeset': m.group(3), 'timestamp': m.group(4), 'user': m.group(5), 'uid': m.group(6)}
+    else:
+        print 'Error way'
+
+def parse_way(text):
+    id = text[4:text.find('"', 6)]
+    return {'id': id}
+
+def parse_tag(text):
+    v_index = text.find('v="')
+    k = text[3:text.find('"', 4)]
+    v = text[v_index + 3:text.find('"', v_index + 4)]
+    return k, v
+
+def get_max_min(nodes):
+	maximum = Geo(nodes[0]['lon'], nodes[0]['lat'])
+	minimum = Geo(nodes[0]['lon'], nodes[0]['lat'])
+	for node in nodes:
+		if node['lat'] > maximum.lat: maximum.lat = node['lat']
+		if node['lat'] < minimum.lat: minimum.lat = node['lat']
+		if node['lon'] > maximum.lon: maximum.lon = node['lon']
+		if node['lon'] < minimum.lon: minimum.lon = node['lon']
+	return minimum, maximum
+
+def parse_osm_file(file_name, silent=False):
+    if not silent:
+        print 'Reading OSM file ' + file_name
+	start_time = datetime.datetime.now()
+	node_map = {}
+	way_map = {}
+	input_file = open(file_name)
+	line = input_file.readline()
+	while line != '':
+		if line[:6] == ' <node':
+			if line[-3] == '/':
+				node = parse_node(line[7:-3])
+				node_map[node['id']] = node
+			else:
+				element = parse_node(line[7:-2])
+				element['tags'] = {}
+		elif line == ' </node>':
+			node_map[node['id']] = element
+		elif line[:5] == ' <way':
+			if line[-3] == '/':
+				way = parse_node(line[7:-3])
+				node_map[node['id']] = node
+			else:
+				element = parse_way(line[6:-2])
+				element['tags'] = {}
+				element['nodes'] = []
+		elif line[:6] == '  <tag':
+			k, v = parse_tag(line[7:-3])
+			element['tags'][k] = v
+		elif line[:5] == '  <nd':
+			element['nodes'].append(line[11:-3])
+		line = input_file.readline()
+	input_file.close()
+    if not silent:
+        print 'File readed in ' + \
+                str(datetime.datetime.now() - start_time) + '.'
+	return node_map, way_map
+
+