new osm backgrounder
TRANSCRIPT
OpenStreetMap Background
• Open Data Project• Build a truly free map of the world• “The Wikipedia of Maps”
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OSM History
• Initiated by Steve Coast in 2005• Started in the UK• Because Ordnance Survey maps were
expensive• Rapidly grew to a worldwide project
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International Variations
• Significant differences country to country
• Europe started mostly from scratch
• US imported a base map based on Census Bureau TIGER road centerline Data in 2007
• In Canada, CANVEC imports are ongoing
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Licensing
• Originally Creative Commons• CC BY-SA was a poor fit to a fact
database• Migrated to ODbL (Open Database
License)• Migration was painful, but is now over
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Differences from Wikipedia
• Wikipedia discourages original research• OSM depends on original research• Edit wars less of an issue
• easily verifiable facts make a big difference
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Differences from Google Maps
• Google Maps is “Free” only in a limited sense (read the ToS)
• Google owns all Intellectual Property• Google does not provide for
community governance
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Other Properties
• No pre-moderation• Different structure than traditional GIS• Two tier model:
• database• data consumers
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The US & TIGER
• TIGER has problems which effectively require us to either review & correct or replace all data
• Long, slow process of Ground Surveys
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OSM Data Model
• Three basic entities
• Node - lat, long
• optional tags
• Way - list of nodes
• direction
• optional tags
• roads, boundaries, entity footprints
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OSM Data Model
• Relations• Bags of nodes, ways & relations• Entities in a relation have roles
• Tags• Key/value pairs• Names, addresses, characteristics
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Tags for Western Avenue
highway=primaryname=Western Avenueref=US 20maxspeed=30 mph
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and we use a relation to bind together all the segments that make up US 20
State of OSM Today
• Excellent Display Map• Reviewed areas generally route well• Lack much address data• POIs incomplete
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TIGER Review
• Some parts of the US are great• Vast rural areas are largely unreviewed• Need more dedicated mappers• But how to persuade them that
reviewing TIGER is worth their time?
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POIs
• Point of Interest databases are hard to collect and hard to keep up to date
• Small businesses open and close with some frequency
• “Enter and forget”
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