A talk at WhereCampEU, Berlin about how we can improve dealing with historical data in OpenStreetMap, and why this is important.

1. OpenStreetMap history
challenges – methods – reasons

2. Relevance of Historical Data
What did the map look
like two years ago?
Who was involved in
editing object X / region Y?
What exactly happened
in changeset Z?

3. Relevance of Historical Data
Historical visualization
Retracing vandalism
Data analysis

4. OpenStreetMap consists of • nodes
• ways
• relations

5. • nodes
• ways
• relations
each of those have a version and a
timestamp, among other things

6. each of those have a version and a
• nodes timestamp, among other things
• ways
• relations
So in theory it’s possible to recreate
the full history of all objects in
OpenStreetMap

7. in practice
this is more
complicated

8. in practice
this is more
complicated ways and
relations
only have
references
to node IDs

9. in practice
this is more
complicated
ways and
relations this poses two
only have problems.
references
to node IDs

10. 1. Moving a node does not
cause a new way version

11. 1. Moving a node does not
cause a new way version
2. References in ways and
relations do not point to a
specific version

12. way version 1
1
v1 3
2
v1
v1
1. Moving a node does not
cause a new way version

13. way version 1
2
v2
1
v1 3
v1
1. Moving a node does not
cause a new way version

14. 2. References in ways and
relations do not point to a
specific version

15. 2. References in ways and
relations do not point to a
specific version

16. 2. References in ways and
relations do not point to a
specific version

17. 2. References in ways and
relations do not point to a
specific version

18. Also, the data is not readily accessible

19. Also, the data is not readily accessible
Full history dump is 451GB of XML,
containing 1.7 billion node versions, 170
million way versions, and
4.5 million relation versions.

20. What is needed?

21. What is needed?
• A suitable DB schema
• PBF format support
• importer (support)

22. What is needed?
• A suitable DB schema
• PBF format support
• importer (support)
.....and ideally, a history API

23. • A suitable DB schema
• PBF format support
• importer support (osmosis, imposm)

24. • A suitable DB schema
• PBF format support
• importer support (osmosis, imposm)
History Hack Weekend
http://bit.ly/osmhistoryhack

26. History Hack Weekend
http://bit.ly/osmhistoryhack
June 10-12
LinuxHotel
Essen, Germany

27. thanks
OSM > mvexel
twitter > @mvexel
Martijn van Exel
all photos from flickr commons