Add script to retrieve Club Mate data from OSM

1 files changed, 166 insertions, 0 deletions

diff --git a/scripts/osmux.py b/scripts/osmux.py
new file mode 100644
index 0000000..88e43ae
--- /dev/null
+++ b/scripts/osmux.py
@@ -0,0 +1,166 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+'''
+
+OSMux - A query multiplexer for the Overpass OpenStreetMap-API
+
+Version 2011-10-22
+
+(c) 2011 - Conrad Hoffmann <ch@bitfehler.net>
+
+This software is public domain and comes without warranty of any kind.
+
+This script splits queries for large areas into several smaller bounding boxes, sends them to them
+to the server and merges the results into a single file (the result for the original query).
+
+Additionally, ways are returned as nodes, so they can be displayed in map overlays. Actually, for
+a matching way the script returns the first node of the way - but with all the tags that were 
+originally attached to the way.
+
+Basic usage instructions available via the --help switch. 
+
+See http://code.bitfehler.net/osmux for more details.
+
+'''
+
+from os import close
+from os import remove
+from sys import stderr
+from time import sleep
+from tempfile import mkstemp
+from argparse import ArgumentParser
+from urllib.request import urlretrieve
+import xml.etree.ElementTree as etree
+
+QUERY_TEMPLATE = 'http://www.overpass-api.de/api/xapi?%s[bbox=%f,%f,%f,%f][%s=%s]'
+
+def log(msg):
+	''' Print a message to the console, unless the 'quiet' flag was set. '''
+	if not params.quiet:
+		print(msg)
+
+def extract(xmlfile):
+	''' Extract nodes from a query result.
+	
+	Regular nodes are just added to the result. For ways, the ways tags are copied to the first
+	node of the way and this first node is added to the result.
+	
+	'''
+	tree = etree.parse(xmlfile)
+	root = tree.getroot()
+	result = {}
+	nodes = {}
+	
+	for child in root:
+		if child.tag == 'node':
+			# Save all nodes in this temp structure, if we are parsing ways we need them later on.
+			nodes[child.attrib['id']] = child
+			# If the node also contains the tag we are looking for, add it to the result.
+			for tag in child:
+				if tag.attrib['k'] == params.tag:
+					result[child.attrib['id']] = child
+		elif child.tag == 'way':
+			# Create a new custom node that contains all of the ways tags and add it to result. If 
+			# a way is returned, it must contain the tag we are looking for, so no need to check.
+			node = nodes[child[0].attrib['ref']]
+			for sub in child:
+				if sub.tag == 'tag':
+					etree.SubElement(node, 'tag', sub.attrib)
+			result[node.attrib['id']] = node
+		elif child.tag == 'remark':
+			# This usually means the query timed out or ran out of memory.
+			print('Potential error: %s' % child.text, file=stderr)
+	
+	return result
+
+# Parse command line arguments.
+parser = ArgumentParser(description='Generate an OpenLayers OSM file using the Overpass API.',
+		epilog='See http://code.bitfehler.net for more details.')
+parser.add_argument('-q', '--quiet', dest='quiet', action='store_true', help='suppress progress messages')
+parser.add_argument('-S', '--step', dest='step', metavar='D', default=1.0, type=float, help='split into steps of D degrees')
+parser.add_argument('-p', '--pause', dest='pause', metavar='P', default=1, type=int, help='pause for P seconds between requests to reduce server load (default: 1, must be >= 0)')
+parser.add_argument('-t', '--tag', dest='tag', metavar='<tag>', type=str, required=True, help='return only elements with this tag')
+parser.add_argument('-v', '--value', dest='value', metavar='<value>', default='*', type=str, help='return only elements with this value (omit for \'*\')')
+parser.add_argument('-s', '--south', dest='south', metavar='S', type=float, required=True, help='latitude of the southern border of the bounding box')
+parser.add_argument('-w', '--west', dest='west', metavar='W', type=float, required=True, help='longitude of the western border of the bounding box')
+parser.add_argument('-n', '--north', dest='north', metavar='N', type=float, required=True, help='latitude of the northern border of the bounding box')
+parser.add_argument('-e', '--east', dest='east', metavar='E', type=float, required=True, help='longitude of the eastern border of the bounding box')
+parser.add_argument('outfile', metavar='<output file>', type=str, help='the output file for the merged OSM data')
+params = parser.parse_args()
+
+# Sanity checks for the arguments.
+if params.pause < 0:
+	print('Value for --pause must be >= 0. Exiting.', file=stderr)
+	exit(1)
+if params.step <= 0:
+	print('Value for --pause must be > 0. Exiting.', file=stderr)
+	exit(1)
+try:
+	open(params.outfile, mode='w', encoding='utf-8')
+except IOError as e:
+	(errno, strerror) = e.args
+	print('Failed to open output file for writing: %s. Exiting.' % strerror, file=stderr)
+	exit(1)
+if min(params.south, params.north) != params.south:
+	print('Value for --south must be less then --north. Use negative numbers for southern hemisphere. Exiting.', file=stderr)
+	exit(1)
+if min(params.east, params.west) != params.west:
+	print('Value for --west must be less then --east. Use e.g. --east 187.5 if you need to cover the 180th meridian. Exiting.', file=stderr)
+	exit(1)
+
+
+(handle, tmpfile) = mkstemp(suffix='.xml', prefix='osm')
+close(handle)
+log("Using temporary file %s, step %f and pause %d." % (tmpfile, params.step, params.pause))
+
+result = {}
+
+cur_lat = params.south
+cur_lon = params.west
+
+while cur_lat < params.north:
+	
+	# While we are in this loop, there are more squares to fetch.
+
+	# We know which square to go for, get its bbox:
+	bbox_lon = [cur_lon, min(cur_lon + params.step, params.east)]
+	bbox_lat = [cur_lat, min(cur_lat + params.step, params.north)]
+	
+	nquery = QUERY_TEMPLATE % ('node', bbox_lon[0], bbox_lat[0], bbox_lon[1], bbox_lat[1], params.tag, params.value)
+	wquery = QUERY_TEMPLATE % ('way', bbox_lon[0], bbox_lat[0], bbox_lon[1], bbox_lat[1], params.tag, params.value)
+	
+	log("Fetching %s" % nquery)
+	urlretrieve(nquery, tmpfile)
+	result.update(extract(tmpfile))
+
+	log("Fetching %s" % wquery)
+	urlretrieve(wquery, tmpfile)
+	result.update(extract(tmpfile))
+	
+	# Calculate the next sub-bbox:
+	if cur_lon + params.step < params.east:
+		# Proceed with next square in current "row":
+		cur_lon += params.step
+	else:
+		# Reset longitude, continue with next "row", if any:
+		cur_lon = params.west
+		cur_lat += params.step
+
+	# Wait a moment - might help the server.
+	sleep(params.pause)
+
+
+log("Removing temporary data file...")
+remove(tmpfile)
+
+log("Generating data...")
+with open(params.outfile, mode='w', encoding='utf-8') as out:
+	out.write('''<?xml version='1.0' encoding='UTF-8'?>
+<osm version="0.6" generator="OSMux (http://code.bitfehler.net/osmux">
+<bound box="%f,%f,%f,%f" origin="Osmosis SNAPSHOT-rexported"/>
+''' % (params.west, params.south, params.east, params.north))
+	for nid in result:
+		node = result[nid]
+		out.write(etree.tostring(node, encoding='utf-8').decode('utf-8'))
+	out.write('</osm>')
+