Correcting OpenStreetMap wrong tag values

As a hobbyist consumer of OSM data to render maps, I find wrong tags annoying. Bad values mean that the resulting map is wrong or incomplete, so less useful. I decided to attack the most egregious ones, which include typos, street names instead of type and some other errors. The idea is to attack the long tail first, so I'm not blocked because the next batch of errors (objects with exactly the same error) looks too big (yes, OCD).

So I hacked a small python script to help me find and edit them:

#! /usr/bin/env python3

import os

import psycopg2


def main():
    db = psycopg2.connect(dbname='europe')
    cursor = db.cursor()

    cursor.execute('''
        SELECT
            count(*) AS count,
            highway
        FROM planet_osm_line
        WHERE
            highway IS NOT NULL
        GROUP BY highway
        ORDER BY count ASC
    ''')
    data = cursor.fetchall()

    for count, highway in data:
        print(f"next {count}: {highway}")

        cursor.execute('''
            SELECT osm_id
            FROM planet_osm_line
            WHERE
                highway = %s
        ''', (highway, ))

        for (osm_id, ) in cursor.fetchall():
            if osm_id < 0:
                # in rendering DBs, this is a relation
                os.system(f"librewolf -P default 'https://www.openstreetmap.org/edit?relation={-osm_id}'")
            else:
                os.system(f"librewolf -P default 'https://www.openstreetmap.org/edit?way={osm_id}'")


if __name__ == '__main__':
    main()

It is quite inefficient, but what I want is to edit the errors, not to write a script :) This requires a rendering database, which I already have locally :)

From here the workflow is:

• Analyze the type of error.
  • This includes looking at the history of the object.
• Search the wiki.
• Correct the error or leave a note.
• Find the original changeset and leave a note if needed.
• Add any details to te changeset if needed.

In my machine, finding the long tail, and finding each set of errors takes one minute, so I was launching two at the same time. One of the things to notice is that if the object you try to edit does no exists anymore, you get and edit view of the whole planet.