Merge pull request #2324 from lonvia/generic-external-postcodes

Rework postcode handling and generalised external postcode support
This commit is contained in:
Sarah Hoffmann
2021-05-13 14:52:19 +02:00
committed by GitHub
20 changed files with 731 additions and 329 deletions

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@@ -2,80 +2,196 @@
Functions for importing, updating and otherwise maintaining the table
of artificial postcode centroids.
"""
import csv
import gzip
import logging
from math import isfinite
from psycopg2.extras import execute_values
from nominatim.db.utils import execute_file
from nominatim.db.connection import connect
def import_postcodes(dsn, project_dir, tokenizer):
""" Set up the initial list of postcodes.
LOG = logging.getLogger()
def _to_float(num, max_value):
""" Convert the number in string into a float. The number is expected
to be in the range of [-max_value, max_value]. Otherwise rises a
ValueError.
"""
num = float(num)
if not isfinite(num) or num <= -max_value or num >= max_value:
raise ValueError()
return num
class _CountryPostcodesCollector:
""" Collector for postcodes of a single country.
"""
with connect(dsn) as conn:
conn.drop_table('gb_postcode')
conn.drop_table('us_postcode')
def __init__(self, country):
self.country = country
self.collected = dict()
def add(self, postcode, x, y):
""" Add the given postcode to the collection cache. If the postcode
already existed, it is overwritten with the new centroid.
"""
self.collected[postcode] = (x, y)
def commit(self, conn, analyzer, project_dir):
""" Update postcodes for the country from the postcodes selected so far
as well as any externally supplied postcodes.
"""
self._update_from_external(analyzer, project_dir)
to_add, to_delete, to_update = self._compute_changes(conn)
LOG.info("Processing country '%s' (%s added, %s deleted, %s updated).",
self.country, len(to_add), len(to_delete), len(to_update))
with conn.cursor() as cur:
cur.execute("""CREATE TABLE gb_postcode (
id integer,
postcode character varying(9),
geometry GEOMETRY(Point, 4326))""")
if to_add:
execute_values(cur,
"""INSERT INTO location_postcode
(place_id, indexed_status, country_code,
postcode, geometry) VALUES %s""",
to_add,
template="""(nextval('seq_place'), 1, '{}',
%s, 'SRID=4326;POINT(%s %s)')
""".format(self.country))
if to_delete:
cur.execute("""DELETE FROM location_postcode
WHERE country_code = %s and postcode = any(%s)
""", (self.country, to_delete))
if to_update:
execute_values(cur,
"""UPDATE location_postcode
SET indexed_status = 2,
geometry = ST_SetSRID(ST_Point(v.x, v.y), 4326)
FROM (VALUES %s) AS v (pc, x, y)
WHERE country_code = '{}' and postcode = pc
""".format(self.country),
to_update)
def _compute_changes(self, conn):
""" Compute which postcodes from the collected postcodes have to be
added or modified and which from the location_postcode table
have to be deleted.
"""
to_update = []
to_delete = []
with conn.cursor() as cur:
cur.execute("""CREATE TABLE us_postcode (
postcode text,
x double precision,
y double precision)""")
conn.commit()
cur.execute("""SELECT postcode, ST_X(geometry), ST_Y(geometry)
FROM location_postcode
WHERE country_code = %s""",
(self.country, ))
for postcode, x, y in cur:
newx, newy = self.collected.pop(postcode, (None, None))
if newx is not None:
dist = (x - newx)**2 + (y - newy)**2
if dist > 0.0000001:
to_update.append((postcode, newx, newy))
else:
to_delete.append(postcode)
gb_postcodes = project_dir / 'gb_postcode_data.sql.gz'
if gb_postcodes.is_file():
execute_file(dsn, gb_postcodes)
to_add = [(k, v[0], v[1]) for k, v in self.collected.items()]
self.collected = []
us_postcodes = project_dir / 'us_postcode_data.sql.gz'
if us_postcodes.is_file():
execute_file(dsn, us_postcodes)
return to_add, to_delete, to_update
with conn.cursor() as cur:
cur.execute("TRUNCATE location_postcode")
cur.execute("""
INSERT INTO location_postcode
(place_id, indexed_status, country_code, postcode, geometry)
SELECT nextval('seq_place'), 1, country_code,
token_normalized_postcode(address->'postcode') as pc,
ST_Centroid(ST_Collect(ST_Centroid(geometry)))
FROM placex
WHERE address ? 'postcode'
and token_normalized_postcode(address->'postcode') is not null
AND geometry IS NOT null
GROUP BY country_code, pc
""")
cur.execute("""
INSERT INTO location_postcode
(place_id, indexed_status, country_code, postcode, geometry)
SELECT nextval('seq_place'), 1, 'us',
token_normalized_postcode(postcode),
ST_SetSRID(ST_Point(x,y),4326)
FROM us_postcode WHERE token_normalized_postcode(postcode) NOT IN
(SELECT postcode FROM location_postcode
WHERE country_code = 'us')
""")
def _update_from_external(self, analyzer, project_dir):
""" Look for an external postcode file for the active country in
the project directory and add missing postcodes when found.
"""
csvfile = self._open_external(project_dir)
if csvfile is None:
return
cur.execute("""
INSERT INTO location_postcode
(place_id, indexed_status, country_code, postcode, geometry)
SELECT nextval('seq_place'), 1, 'gb',
token_normalized_postcode(postcode), geometry
FROM gb_postcode WHERE token_normalized_postcode(postcode) NOT IN
(SELECT postcode FROM location_postcode
WHERE country_code = 'gb')
""")
try:
reader = csv.DictReader(csvfile)
for row in reader:
if 'postcode' not in row or 'lat' not in row or 'lon' not in row:
LOG.warning("Bad format for external postcode file for country '%s'."
" Ignored.", self.country)
return
postcode = analyzer.normalize_postcode(row['postcode'])
if postcode not in self.collected:
try:
self.collected[postcode] = (_to_float(row['lon'], 180),
_to_float(row['lat'], 90))
except ValueError:
LOG.warning("Bad coordinates %s, %s in %s country postcode file.",
row['lat'], row['lon'], self.country)
cur.execute("""
DELETE FROM word WHERE class='place' and type='postcode'
and word NOT IN (SELECT postcode FROM location_postcode)
""")
conn.commit()
finally:
csvfile.close()
with tokenizer.name_analyzer() as analyzer:
analyzer.add_postcodes_from_db()
def _open_external(self, project_dir):
fname = project_dir / '{}_postcodes.csv'.format(self.country)
if fname.is_file():
LOG.info("Using external postcode file '%s'.", fname)
return open(fname, 'r')
fname = project_dir / '{}_postcodes.csv.gz'.format(self.country)
if fname.is_file():
LOG.info("Using external postcode file '%s'.", fname)
return gzip.open(fname, 'rt')
return None
def update_postcodes(dsn, project_dir, tokenizer):
""" Update the table of artificial postcodes.
Computes artificial postcode centroids from the placex table,
potentially enhances it with external data and then updates the
postcodes in the table 'location_postcode'.
"""
with tokenizer.name_analyzer() as analyzer:
with connect(dsn) as conn:
# First get the list of countries that currently have postcodes.
# (Doing this before starting to insert, so it is fast on import.)
with conn.cursor() as cur:
cur.execute("SELECT DISTINCT country_code FROM location_postcode")
todo_countries = set((row[0] for row in cur))
# Recompute the list of valid postcodes from placex.
with conn.cursor(name="placex_postcodes") as cur:
cur.execute("""SELECT country_code, pc, ST_X(centroid), ST_Y(centroid)
FROM (
SELECT country_code,
token_normalized_postcode(address->'postcode') as pc,
ST_Centroid(ST_Collect(ST_Centroid(geometry))) as centroid
FROM placex
WHERE address ? 'postcode' and geometry IS NOT null
and country_code is not null
GROUP BY country_code, pc) xx
WHERE pc is not null
ORDER BY country_code, pc""")
collector = None
for country, postcode, x, y in cur:
if collector is None or country != collector.country:
if collector is not None:
collector.commit(conn, analyzer, project_dir)
collector = _CountryPostcodesCollector(country)
todo_countries.discard(country)
collector.add(postcode, x, y)
if collector is not None:
collector.commit(conn, analyzer, project_dir)
# Now handle any countries that are only in the postcode table.
for country in todo_countries:
_CountryPostcodesCollector(country).commit(conn, analyzer, project_dir)
conn.commit()
analyzer.update_postcodes_from_db()

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@@ -13,12 +13,6 @@ from nominatim.version import NOMINATIM_VERSION
LOG = logging.getLogger()
def update_postcodes(dsn, sql_dir):
""" Recalculate postcode centroids and add, remove and update entries in the
location_postcode table. `conn` is an opne connection to the database.
"""
execute_file(dsn, sql_dir / 'update-postcodes.sql')
def recompute_word_counts(dsn, sql_dir):
""" Compute the frequency of full-word search terms.