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My presentation in The 13th AGILE International Conference on Geographic Information Science (AGILE'2010), 10-14 May 2010, Guimarães, Portugal
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Quality in User GeneratedSpatial ContentCarmen Brando, Bénédicte Bucher
AGILE Conference 2010Guimarães, May 10 - 14
Institut Géographique National (IGN), FranceCogit Lab.
1© IGN - 2010
What’s it about?
Generated by: http://www.wordle.net
SC: Spatial ContentUGC: User Generated ContentUGSC: User Generated Spatial Content
2© IGN - 2010
What’s it about?
Flickr
Wikipedia
Creation of Spatial Content (SC): Geotagging
3© IGN - 2010
What’s it about?
Wikimapia
OpenStreet Map
Creation of Spatial Content (SC): Features Editing
4© IGN - 2010
What’s it about?
5Generated by: http://www.wordle.net
SC: Spatial ContentUGC: User Generated ContentUGSC: User Generated Spatial Content © IGN - 2010
Outline
• Quality• in User Generated Content (UGC)• of Spatial Content (SC)• in User Generated Spatial Content (UGSC)
• Proposed Approach• Conclusion and Perspectives
6© IGN - 2010
Quality in User Generated Content (UGC): Definition
• is related to• whether is useful or not to users’ purposes:
fitness for use• users’ trust in the content: producer’s authority
• Wikipedia, best example of UGC, but…• quality issue: users are anonymous
• Wikis, easy and fast content edition• More advance collaborative editing tools assure
content consistency by reconciling concurrent operations• e.g. Google Wave
7© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
• During Edition: Internal Coherence and Citing External Sources
Quality in User Generated Content (UGC): How to Improve it?
8© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
• During Edition: Authority, Comprehensiveness and Collaboration Mechanisms
Quality in User Generated Content (UGC): How to Improve it?
9© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Quality in User Generated Content (UGC): How to Improve it?
• After Edition• Comparison with a Reference Source :
• Wikipedia vs. Encyclopedia Britannica (Nature 2005)
• Quantitative Measures : • Number of Edits, Number of Editors, Intensity of Cooperative
Behavior, Analysis of Featured Articles, etc. (Wilkinson, 2007) (Stvilia, 2005) (Mcguinness, 2006) and more…
• Revision History• Conflicts Detection/Reconciliation
10© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Quality in User Generated Content (UGC): How to Improve it?
Users manually resolve conflicts
11© IGN - 2010
Conflicts Detection/Reconciliation
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Quality of Spatial Content (SC): Definition
12
Real World
Ideal Representation(Nominal Terrain)
Specifications*
© IGN - 2010
* Buildings of area greater than 20m2
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Quality of Spatial Content (SC): Definition
IGN’s BD TOPO ®
Knowledge about how the real world is observed and how it is modeled in the database 13
NMA Specifications
© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Quality of Spatial Content (SC): Definition
14
Real World
Ideal Representation(Terrain Nominal)
Produced Data +Metadata (Specifications + Error Criteria)
InternalQuality
Specifications*
Production Process: Errors**
ExternalQuality
User’s Required Data
* Buildings of area greater than 20m2** Maybe mistakes have been made or reality has evolved
© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Quality in User Generated Spatial Content (UGSC)
• UGSC for updating NMA's and private mapping organizations data through alerts
• OpenStreet Map, great influence in the way SC is produced and updated
• More recently, UGSC for complementing NMA's and private mapping organizations data through content edition (beyond simple alerts)
(Budhathoki, 2008) (Elwood, 2008) (Antoniou, 2009)15
© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Quality in User Generated Spatial Content (UGSC)
• Qualification of contributors and contributions• A contributors' classification based on• their purposes (Coleman et al., 2009)• their geographic locations (Goodchild, 2009)• their trust relations with other users (Bishr et al., 2007)
• Distinguish between high and low value contributions• Rating systems (Elwood, 2008)• Marking regions with problems (Maué et al., 2008)• Comparison with reference source (Haklay, 2009)
16© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Proposed Approach: Specifications for UGSC?
• Certainly, this is appropriate for NMA’s and private mapping organizations
• What about Neogeography?• Neogeographers would be reluctant to provide
and work according specifications
17© IGN - 2010
© Scott Adams
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Proposed Approach:Specifications for UGSC?
Guidelines
Tags ReferenceTags Reference
18© IGN - 2010
Proposed Approach:Specifications for UGSC?
•Done by Keep Right!
http://keepright.ipax.at•Predefined integrity constraints are verified on OSM data•For instance, intersections without junctions
19© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Proposed Approach:Specifications for UGSC?
Before
After
• OSM Web Editor: Potlatch• Constraint: Intersections Without Junctions
20© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Proposed Approach:Specifications for UGSC?
• Special interest groups (Coote, 2008) have • stronger requirements on data quality• budget limitations for collecting, redacting and updating
specifications• lack of expertise on modeling techniques to ensure a user
generated spatial content (UGSC) consistency• interest in accepting some rules during contribution
• Therefore, assisting users to provide content specifications is important for them
21
Yes We Can
© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Proposed Approach: UGSC Specifications
• Assist users to provide specifications of their content for quality management
• UGSC Specifications1. to support on the fly consistency checking (e.g. 'a road
cannot intersect a river')2. to check consistency with external reference data,
reusing an existing model (Abadie, 2009)3. to reconcile concurrent editions of data (e.g. 'the
attribute name of a road is independent from geometry')
22© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Proposed Approach:Consistency Checking
• Lack of geometrical consistency between those feature types
• UGSC Specifications: An integrity constraint indicating the relation between these two features (Geometry sharing)
• Possible Reparation: placing automatically the line boundary throughout the middle of the waterwayOSM data corresponding to administrative
boundaries and waterways around theFrench city of Grenoble (December 2009)
23© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Proposed Approach: UGSC Specifications
• Assist users to provide specifications of their content for quality management
• UGSC Specifications1. to support on the fly consistency checking (e.g. 'a road
cannot intersect a river')2. to check consistency with external reference data,
reusing an existing model (Abadie, 2009)3. to reconcile concurrent editions of data (e.g. 'the
attribute name of a road is independent from geometry')
24© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Proposed Approach:Reconciliation Mechanism
25
Tajel© Jorge Cham
© IGN - 2010
Cecilia© Jorge Cham
Changing name to ‘Avenue Bollée’
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Rue de Paris
Avenue Bollée
Adding a road segment to ‘Rue de Paris’
??UGSC Specification:
'the attribute name of a road is independent from geometry'
Conclusion
• UGSC refers to new paradigm for producing SC• UGSC quality management from a NMA’s point of
view• Users describe their content in the form of
specifications to fit their purposes, if possible using reference data set
• Users improve UGSC quality by contributing with SC in a collaborative manner
26© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
Perspectives
• Test our approach (on-going work) in the Geoxygene Plataform: http://oxygene-project.sourceforge.net, considering IGN data
• Eventually elucidate which elements should be considered in UGSC metadata
27© IGN - 2010
Quality in UGC Quality of SC Quality in UGSC Proposed Approach Conclusion & Perspectives
• Thank you for listening!
• Any questions?
• Contact information: • [email protected]• [email protected]
28© IGN - 2010
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