changes

Imposm-Changes

Imposm-Changes imports OpenStreetMap changeset information and metadata into a PostgreSQL/PostGIS database.

The resulting database can be used to build change monitoring and QA applications. OSM Observer is such an application.

Uses an limitations

Imposm-Changes imports planet dumps and extracts (.osm.pbf), diff files (.osc.gz) and changeset files (.osm.gz).

It should work for whole planet imports but is not optimized for. You will typically use the changes_bbox option to monitor a smaller region/country extent. This allows you to monitor the changes of the last few weeks with moderate server requirements.

Installation

go get -u github.com/omniscale/imposm-changes
go install github.com/omniscale/imposm-changes/cmd/imposm-changes

Run

mkdir imposm-changes
cd imposm-changes
cp $GOPATH/src/github.com/omniscale/imposm-changes/config.json ./

# Edit config.json with database connection and changes_bbox.

# Call `import` to make initial import.
imposm-changes -config config.json import path/to/initial.osm.pbf

# Call `run` to continuously download and import diff and changes files. 
# Start this via systemctl or similar in production.
# Make sure initial_history in config.json is large enough to cover all
# changes since the creation of your initial osm.pbf file.
imposm-changes -config config.json run

Example queries

Here are a few example queries, that demonstrate what you can do with the resulting database.

Count changes in the last 8 hours within a bounding box:

SELECT count(*) FROM changesets
WHERE bbox IS NOT NULL AND bbox && ST_MakeEnvelope(6.8, 50.8, 7.2, 52.6)
AND closed_at > (NOW() - INTERVAL '8 hours');

Count how many nodes where added, modified or deleted:

SELECT sum(case when add then 1 else 0 end) AS add,
       sum(case when modify then 1 else 0 end) AS modify,
       sum(case when delete then 1 else 0 end) AS delete
FROM nodes
WHERE changeset IN (
    SELECT id
    FROM changesets
    WHERE closed_at > (NOW() - INTERVAL '8 hours')
);

Query information about nodes that where added or modified by Open Wheelmap.Org:

SELECT id, add, modify, version, ST_AsText(geometry), tags, timestamp
FROM nodes
WHERE (add OR modify)
AND changeset IN (
    SELECT id
    FROM changesets
    WHERE tags->'comment' = 'Modified via wheelmap.org'
);