| 39 | |
| 40 | |
| 41 | def query_osm(osm_type, osm_id): |
| 42 | if os.path.exists(OSM_CACHE): |
| 43 | with open(OSM_CACHE, 'r') as f: |
| 44 | cache = json.load(f) |
| 45 | else: |
| 46 | cache = {} |
| 47 | k = '{}{}'.format(osm_type, osm_id) |
| 48 | if k in cache: |
| 49 | coord = cache[k] |
| 50 | return (coord[1], coord[0]) |
| 51 | |
| 52 | OSM_API_SERVER = 'https://api.openstreetmap.org/api/0.6' |
| 53 | try: |
| 54 | r = urllib.request.urlopen('{}/{}/{}{}'.format( |
| 55 | OSM_API_SERVER, osm_type, osm_id, '/full' if osm_type != 'node' else '')) |
| 56 | except OSError as e: |
| 57 | logging.warn('Could not download %s %s: %s', osm_type, osm_id, e) |
| 58 | return None |
| 59 | xml = etree.parse(r) |
| 60 | nodes = {} |
| 61 | for nd in xml.findall('node'): |
| 62 | nodes[nd.get('id')] = (float(nd.get('lat')), float(nd.get('lon'))) |
| 63 | ways = {} |
| 64 | for way in xml.findall('way'): |
| 65 | coord = [0, 0] |
| 66 | count = 0 |
| 67 | for nd in way.findall('nd'): |
| 68 | count += 1 |
| 69 | for i in range(len(coord)): |
| 70 | coord[i] += nodes[nd.get('ref')][i] |
| 71 | ways[way.get('id')] = [coord[0] / count, coord[1] / count] |
| 72 | |
| 73 | coord = None |
| 74 | if osm_type == 'node': |
| 75 | coord = nodes[str(osm_id)] |
| 76 | elif osm_type == 'way': |
| 77 | coord = ways[str(osm_id)] |
| 78 | else: |
| 79 | for el in xml.findall(osm_type): |
| 80 | if el.get('id') == str(osm_id): |
| 81 | coord = [0, 0] |
| 82 | count = 0 |
| 83 | for m in el.findall('member'): |
| 84 | if m.get('type') == 'node' and m.get('ref') in nodes: |
| 85 | count += 1 |
| 86 | for i in range(len(coord)): |
| 87 | coord[i] += nodes[m.get('ref')][i] |
| 88 | elif m.get('type') == 'way' and m.get('ref') in ways: |
| 89 | count += 1 |
| 90 | for i in range(len(coord)): |
| 91 | coord[i] += ways[m.get('ref')][i] |
| 92 | if count > 0: |
| 93 | coord = [coord[0] / count, coord[1] / count] |
| 94 | if coord is None: |
| 95 | return None |
| 96 | |
| 97 | cache[k] = coord |
| 98 | with open(OSM_CACHE, 'w') as f: |