volunteered geographic information and openstreetmap
DESCRIPTION
Short introduction to the subject of Volunteered Geographic Information and outlining some of the characteristics, issues themes of VGI and then a comprehensive talk about the OpenStreetMap Project. By Tim Waters, at AGI Northern Group (SIG), April 2009, Manchester UniversityTRANSCRIPT
“OpenStreetMap is a free editable map of the world made by people like you!”
AGI NORTH 23 April 2009
About Tim
Tim WatersFreelance GIS Consultantand Web Developer
Long time OpenStreetMap contributor & evangelist
Leeds UK
blog: http://thinkwhere.wordpress.com
latest: http:www.MapWarper.net
VGI
Volunteered Geographic Information (VGI) is the harnessing of tools to create, assemble, and disseminate geographic data provided voluntarily by individuals (Goodchild, 2007).
Some examples of this phenomenon are Wikimapia, OpenStreetMap, and Google MyMaps.
These sites provide general base map information and allow users to create their own content by marking locations where various events occurred or certain features exist, but aren’t already shown on the base map.
VGI is a special case of the larger Web phenomenon known as user-generated content.
Straight outa Wikipedia.............there's more pictures later.
VGI
1. Potential of VGI to expand/complete/improve existing databases, infrastructures, & archives;
2. Potential of VGI to enable us to gather/produce new forms of spatial information that use local knowledge to inform previously un-answerable questions, unknowable phenomenon, and new social and political practices. (“new knowledge practices”)
Power of Volunteered Geographic Information
Concerns:
what drives people to do this, how accurate are the results, will they threaten individual privacy, and how can they augment more conventional sources
Basics:Web2 – web search, Google, communitiestechnologies, GPS cameras, network, computersCrowd sourcing
price, closed of NMAs (OS licences) Push factor
OpennessEasyAmateur---
Future with NMAs etc. Decline in world mapping. Remote sensing and VGI filling in the gap.Mapping economically determined. None in developing world. Expensive to keep up to date.
AND Map2.0
WIKIMAPIA
Go
og
le Earth
!
Flickr Shapefiles
ARGH!!!! Just show me some nice maps
Maps!
You can get the data. downloads.cloudmade.com
Berlin
Copenhagen
Amsterdam
Madrid
NYC
Baghdad
Sydney
Pretoria
Kinshasa
Map what you like
Germany 2006Germany 2006
Germany 2007Germany 2007
Germany 2008Germany 2008
Most other maps are non-freeVector data for custom maps is difficult to obtain
licencesUsers can improve the mapFast updatesCommercial maps have intentional errorsMany areas of the world are mapped poorlySpeciality mapsInnovative uses
OSM in a nutshell
Mapping data is not free
Not free as in freedom
Maps CopyrightMaps Copyright
The maps are based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Luton Borough Council. 100023935, 2006
The Ordnance Survey map data included within this web site is provided by Luton Borough Council under licence from the Ordnance Survey in order to fulfil its public function to act as a local authority. Persons viewing this mapping should contact Ordnance Survey copyright for advice where they wish to licence Ordnance Survey map data for their own use
Full of mistakes, car centred
Mistakes cannot be corrected
Cannot re use or reprint
Coverage economically determined
Change happens
inflexible
Katrina
100,000 users100,000 users330 million nodes330 million nodes800million trackpoints800million trackpoints1 Billion Tags1 Billion Tags
Donate data & free data
Tiger / Line
Other Sources:DonationsGaza, people donated to buyimagery for OSM
Yahoo allow use of imagery
Landsat
http://www.MapWarper.net
Or, just D.I.Y!Mapping party
Mapping Parties Galore!
Mapping Party Field Trip7 June SundayPatley Bridge
Mikels Case Study - Brighton
How to do it?Editors, online.
Do it from home!
Case Study:
Mikel in Brighton
Mapping Party, September 2006
OSM Brighton, December 2006
Summer 2007
TodayWinter 2007
Today
1.0
His Process
Download existing data to GPS
Print Out Map for Notes, Bicycle
Network Diagram
Upload GPS Tracks to Computer
Upload Tracks
Draw Over Them
Editing in Potlatch, rollbacks, history
Tech
The OSM-”Tool Chain”
API(Rails)
Potlatch(Flash)
JOSM(Java)
Database
...
Renderer
Mapnik
tiles@home
osmarender,pdfatlas,
...
planetdump
MySQL
Viewer
SlippyMap
(OpenLayers)
“Google”tiles
“Google”tiles
Editors
http://api.openstreetmap.org/api/0.4/way/35
<way id='7972254' timestamp='2007-09-24T12:36:29+01:00' user='chippy' visible='true'> <nd ref='59608510' /> <nd ref='59608509' /> <nd ref='59608516' /> <nd ref='59608515' /> <nd ref='59608514' /> <nd ref='59608513' /> <nd ref='59608512' /> <nd ref='59608511' /> <nd ref='59608510' /> <tag k='created_by' v='JOSM' /> <tag k='building' v='retail' /> <tag k='name' v='White Rose Shopping Centre' /> <tag k='amenity' v='shopping_centre' /> <tag k='note' v='huge building' /> </way>
RESTful API
Trackpoints
Nodes
Ways
highway = residentialname = Chestnut Laneoneway = truesurface = flags
highway = primaryname = Otley Roadref = A660
Tags!
http://wiki.openstreetmap.org/index.php/Map_features
amenity = hospitalname = Saint Jamesemergency = yesPOIs
Areas
leisure=nature_reserve
simple data format
tagging for metadata
standard map tiles
Volunteers.
OSM donation driveOver $22,500 raised in 3 days for new server in early February
Goal was $15,000servers
api 0.6downtime
API 0.6
Changesets
user id
version numbersDiffs can be applied
Licence
Now:Creative Commons by Share Alike
Future:Open Database Licence
CC = everything is shared alikeOdbL = only the database should be shared
Both allows commerical use
healthy ecosystem
toolsrendererseditorsroutersapplications
Potlatch
JOSM
Merkaartor
Mapnik
ORS
Many mobile apps
Freemap Slovakia & contours
Cycle Map
OpenPisteMap
Open Street Bugs
healthy ecosystem
toolsrendererseditorsroutersapplications
Ecology
System
Iteration
Gets better & stronger
Folksonomy
But with standardised conventions.
Votingmapping realityproposedadoption
iteration
landuse=vineyard vslanduse=farmcrop=grapes
Edit Wars
Taking a leaf.Tapping the crowd.
Map Maker from Google.
AND Map2.0
Peoples Map (dot dot dot)
QualityIs it any good?
OSM is sometimes the ONLY source for mapping dataMap ActionDeveloping World
How good it the data? − Positional accuracy− Completeness− Attribute accuracy and completeness− Consistency − Semantic accuracy− Temporal quality (up-to-date-ness)
Dair Grant
Errors in Google / Teleatlas
Errors in OSMbut, they can be fixed :)
OSM 193 bugs per 10km2
Google 89 bugs per 10km2
http://blog.fortiusone.com/2008/12/12/openstreetmap-vs-googleteleatlas-street-coverage/OpenStreetMap vs. Google/TeleAtlas Street Coverage
The size of the circles are proportional to the values for both, so small circles equal poor coverage and large circles equal good coverage. The overlap of the circles shows who appears to be doing better (orangey/brown showing means that osm is doing better, blue google). OSM is the top layer so a tie will have OSM looking better, but you can click the layers on and off to see both views of the coverage.
The data is very interesting. Quickly comparing the roads layers against OSM in Kenya show
good correspondence where there is Yahoo aerial imagery to trace against — if OSM had access to the same imagery,
I imagine we’d be pretty much equivalent country-wide. MapMaker is slightly more complete in central Nairobi; I put that down to Google
having full time employees in Nairobi who work on MapMaker
Green = OSMPurple = Mapmaker
http://povesham.wordpress.com/2008/08/07/osm-quality-evaluation/ UCL Muki Haklay http://www.ucl.ac.uk/~ucfamha/OSM%20data%20analysis%20070808_web.pdf
OSM VS OSCoverageBlue = OSM better
Meridian 2 and OSM – Motorway comparison
http://povesham.wordpress.com/2008/08/07/osm-quality-evaluation/ UCL Muki Haklay http://www.ucl.ac.uk/~ucfamha/OSM%20data%20analysis%20070808_web.pdf
Positional accuracy
On each tile, 100 points sample with evaluation of distance between OSM and Meridian 2
Can see significant differences: from about 3m to over 8m
Area Average difference (m)
Barnet 6.77
Highgate 8.33
New Cross 6.04
South Norwood 3.17
Sutton 4.83
Total 5.83
http://povesham.wordpress.com/2008/08/07/osm-quality-evaluation/ UCL Muki Haklay http://www.ucl.ac.uk/~ucfamha/OSM%20data%20analysis%20070808_web.pdf
The analysis shows that, where OSM was collected by several users and benefited from some quality assurance, the quality of the data is comparable and can be fit for many applications.
The positional accuracy is about 6 metres, which is expected for the data collection methods that are used in OSM. The comparison of motorways shows about 80% overlap between OSM and OS .
The challenges are the many areas that are not covered – currently, OSM has good coverage for only 25% of the land area of England
12 Months ago...http://povesham.wordpress.com/2008/08/07/osm-quality-evaluation/ UCL Muki Haklay http://www.ucl.ac.uk/~ucfamha/OSM%20data%20analysis%20070808_web.pdf
Thanks!
Tim Waters http://thinkwhere.wordpress.com
Field Trip!7 June SundayPatley Bridge