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Nominatim/nominatim/api/v1/helpers.py
2023-05-24 22:54:54 +02:00

72 lines
2.7 KiB
Python

# SPDX-License-Identifier: GPL-3.0-or-later
#
# This file is part of Nominatim. (https://nominatim.org)
#
# Copyright (C) 2023 by the Nominatim developer community.
# For a full list of authors see the git log.
"""
Helper function for parsing parameters and and outputting data
specifically for the v1 version of the API.
"""
from nominatim.api.results import SearchResult, SearchResults, SourceTable
REVERSE_MAX_RANKS = [2, 2, 2, # 0-2 Continent/Sea
4, 4, # 3-4 Country
8, # 5 State
10, 10, # 6-7 Region
12, 12, # 8-9 County
16, 17, # 10-11 City
18, # 12 Town
19, # 13 Village/Suburb
22, # 14 Hamlet/Neighbourhood
25, # 15 Localities
26, # 16 Major Streets
27, # 17 Minor Streets
30 # 18 Building
]
def zoom_to_rank(zoom: int) -> int:
""" Convert a zoom parameter into a rank according to the v1 API spec.
"""
return REVERSE_MAX_RANKS[max(0, min(18, zoom))]
def deduplicate_results(results: SearchResults, max_results: int) -> SearchResults:
""" Remove results that look like duplicates.
Two results are considered the same if they have the same OSM ID
or if they have the same category, display name and rank.
"""
osm_ids_done = set()
classification_done = set()
deduped = SearchResults()
for result in results:
if result.source_table == SourceTable.POSTCODE:
assert result.names and 'ref' in result.names
if any(_is_postcode_relation_for(r, result.names['ref']) for r in results):
continue
classification = (result.osm_object[0] if result.osm_object else None,
result.category,
result.display_name,
result.rank_address)
if result.osm_object not in osm_ids_done \
and classification not in classification_done:
deduped.append(result)
osm_ids_done.add(result.osm_object)
classification_done.add(classification)
if len(deduped) >= max_results:
break
return deduped
def _is_postcode_relation_for(result: SearchResult, postcode: str) -> bool:
return result.source_table == SourceTable.PLACEX \
and result.osm_object is not None \
and result.osm_object[0] == 'R' \
and result.category == ('boundary', 'postal_code') \
and result.names is not None \
and result.names.get('ref') == postcode