● Objects with
– A position/extent
– A number of Tags (key=value)
– complete list of attributes
– no ontology
– no hierarchy
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?
We reject: kings, presidents and voting.
We believe in: rough consensus and running
(David D. Clark)
● 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
We don't need no metadata....
● No formal metadata
● Just freetext wiki explanations
● Work needed to extract usable data
Fulltext vs. metadata
Google vs. Library
Data mining vs. lookup
● Statistics about actual use
● Look at the data and infer metadata
● Needs large body of data
● Doesn't work for new tags
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