Openstreetmap, GPS traces and positioning

OpenStreetMap and positioning
JaakLainesteOpenStreetMap Estonia
Nutiteq.com

OpenStreetMap
Wikipedia of maps
Global database
Focused to current street maps
No elevation, history etc
Community
300.000+ registered users
Very strong in Germany
Free and open to use
CC-BY-SA license

How OSM is created
Field mapping
GPS traces
Walking Papers – paper notes
On-screen mapping
Yahoo! Imagery
Regional sources: e.g. Estonian National Land Board
Imports
USA: TIGER data
Europe: Corine Land Cover etc

Mapping parties

Data in OSM Databases
Map data
Nodes, ways, relations
Tagged openly
History: who, when, changesets
GPS traces
Base for map

GPS Trace data
HTTP REST-based API
Based on BBOX
Tracks and trackpoints (lat/long)
No timestamp, user ID
GPX format (simple XML)
Someone has been in point X
Track details from database
Timestamp, user ID

Map data
Ways and nodes:
User ID
Editing time
Information about locations:
Probably editor has been in the point around editing time (+ maybe few weeks)
Density of different editors
Quite ambiguous

London – different editors
ITOWorld extract

Using OSM data
GPS track
High precision – time and location
Less users
Map locations
Low precision
More users
Movement distribution
Places what and when users have visited

OSM advantages
Coverage is:
Global
Quick, get the data now
Free
Real usability?
Real coverage is variable

Coverage statistics
http://wiki.openstreetmap.org/wiki/Statistics
Registered users: ~300,000, <5% active
About 6,000 editors/week
Tracks
Points: ~200,000,000,000
Traces: 800,000 traces
Map nodes: ~ 750,000,000

Key issues
User is in „mapping mode“. May be special trip
Most mappers do not upload/share GPS traces
User can trace aerials, without being there
Regional differences
Very good in e.g. Germany, UK
Limited in e.g. US (TIGER imports)

Other uses of OSM
Use OpenStreetMap as a base map
Positioning accuracy improvement
GPS trace shows where people are more probably
Share your GPS traces in OSM
Contribute to OSM
fix map of your neighbourhoods!

Study: distribution of GPS traces
Two random cities picked
Tartu, Estonia – well-known town
Weimar, Germany – unknown town
GPS traces downloaded for town area
Tartu – 9x9 km, 160.000 points, 42 tracks
Weimar – 7x7 km, 100.000 points, 33 tracks
Spatial distribution of traces
Visualized in 50 or 100-m grid

Tartu map in OSM

Tartu GPS traces

Tartu, 100m grid of GPS points

Weimar map

Weimar, GPS trackpoints

Weimar, 50m grid

Map of central London

GPS traces

GPS points on map

London grid
Points: 440 000, tracks: 220

Thank you!
Jaak Laineste
jaak@openstreetmap.ee
www.openstreetmap.org
wiki.openstreetmap.org
Credits: Microsoft support for fixing my PowerPoint

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Openstreetmap, GPS traces and positioning

by Jaak Laineste on Aug 28, 2010

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