14. Collecting attributes
● On foot, by bike, car, train, ...
● Tracks and waypoints
● Notes on paper
● Audio notes
● Photos
● Out of copyright maps
15. Aerial Images
● Aerial/Satellite Images
● From Landsat
● From Yahoo
● ...
16.
17. Data model
● “The simplest thing that could possibly work.”
(Ward Cunningham)
● All data stored in central database
● Geometric objects
● With history
20. Data model
● Objects with
– A position/extent
– A number of Tags (key=value)
● No
– class/attributes
– complete list of attributes
– no ontology
– no hierarchy
21. Where do tags come from?
● Invented as needed by people needing them
● Discussion on mailing lists and wiki
● Documentation in wiki
● Voting process (mostly ignored)
● Reorganization needed?
● Coexisting schemes?
22. Rough consensus
We reject: kings, presidents and voting.
We believe in: rough consensus and running
code.
(David D. Clark)
23. Problems
● Tagging “for the renderers”
● Tagging only for current use of data
● Much of the available information is therefore
not stored and will be lost
● Might need costly reacquisition of data
24. We don't need no metadata....
● No formal metadata
● Just freetext wiki explanations
● Work needed to extract usable data
25. Data mining
Fulltext vs. metadata
Google vs. Library
Data mining vs. lookup
26. Tagwatch
● Statistics about actual use
● Look at the data and infer metadata
● Needs large body of data
● Doesn't work for new tags
27. www.openstreetmap.org
www.geofabrik.de
Jochen Topf
jochen.topf@geofabrik.de
All maps in this talk are Copyright 2008 OpenStreetMap Contributors
The talk itself is Copyright 2008 Jochen Topf
Licence for maps and talk: Creative Commons CCBYSA
