OSM Background

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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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OSM in the Capital District

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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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OpenCycleMap

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TopOSM

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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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Support Tools

• ITOWorld - Tiger Reviewed Map

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Capital District

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South of Albany

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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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Addresses

• Where do we get them?• Enhanced 911?• Parcel Data?• On Foot?

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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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Pause for General OSM Questions

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