Specifications for User Generated Spatial Content
Carmen Brando, Bénédicte Bucher, Nathalie AbadieCOGIT Laboratory – Institut Géographique National (IGN), France
AGILE Conference 2011Utrecht, 18 – 21 April
© IGN - 2011
Context: Issues in OSM
2
Topology Geometry sharing
See (Bishr and Kuhn 2007; Elwood 2008; Goodchild 2009; Brando and Bucher 2010)
Loose (not explicit) semantics
Context Objectives Proposed Approach Conclusion & Perspectives
Context: Wikipedia
3
Wikipedia policy on external sources citation in articles http://en.wikipedia.org/wiki/Wikipedia:Citing_sources
Context Objectives Proposed Approach Conclusion & Perspectives
Context: Wikipedia
4
Category section of the article rapid transit
Extract of a paragraph of the article rapid transit
(internal links in blue)
Infobox public transit
Context Objectives Proposed Approach Conclusion & Perspectives
Geometry sharing” pedestrian footpaths touch
water trails”
Conceptual schema
Context: NMA
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What do I call a path?
Which paths do I represent in the database?
How do I represent a path? Path- nature= {way, footpath,
cycle path}- linear geometry- crossing = {bridge, tunnel,
ford}
Ontology
Acquisition rules” pedestrian footpaths are less
than 1.5m wide”
Valle de las Leñas:
near route 40 in Argentina
(photo source: Panoramio)
What is the relation between pedestrian footpaths and water
trails?
Specifications
Context Objectives Proposed Approach Conclusion & Perspectives
Objective (PhD) To address the challenge of quality and usability in
collaborative edition of spatial content by:
Reconciliation and evaluation mechanisms: for automatic
consistency checking, integration of different contributions, comparison
with reference data
Formal VGI specifications
= modeling items as for conventional spatial content specifications
(reusing Abadie et al 2010’s proposal),
+ relevant relationships between data (e.g. geometry sharing),
+ relationships to external reference data (e.g. NMA’s data)
6
Context Objectives Proposed Approach Conclusion & Perspectives
VGI Feature
Type
NMA Ontology
Concept
Attribute
Type
Objective (Paper)
7Diagram of the proposed VGI specifications (non-exhaustive)
Geometry
TypeNMA Feature
Type
Context Objectives Proposed Approach Conclusion & Perspectives
Relevant
Relationship
<xml> .…
.</xml>
VGI
keywords
Suggested composition
relationships
(possibly with external
reference data)
Road section- coating- # lanes- linear
NMA formal specificationsUser
Generated
vocabulary (richer and more
structured)
Related NMA’s
modeling
elements
Train station- name- capacity- surface
<owl: class > .…
.</owl: class>
Proposed Approach
Module #1: the
Wikipedia retriever
Module #2:
the NMA
connector
Module #3: the relationship finder
Context Objectives Proposed Approach Conclusion & Perspectives
9
Proposed Approach
I want to report a new bus stop
Cecilia© Jorge Cham
Excerpt of OSM Map centered on
Houston, Texas
keyword: bus stop
Context Objectives Proposed Approach Conclusion & Perspectives
10
Module #1: the Wikipedia retriever
Context Objectives Proposed Approach Conclusion & Perspectives
Module #1: the Wikipedia retriever
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{{ Infobox station| … | address = | line = | coordinates = | structure = | platform =| depth = | levels = | tracks = | opened = | closed = |…
}}
Wikipedia Infobox for stations defined in wikicode
Context Objectives Proposed Approach Conclusion & Perspectives
<owl:Class rdf:ID=“station">
<rdfs:label xml:lang="fr">station de voyageurs</rdfs:label>
<rdfs:label xml:lang="en">passenger station</rdfs:label>
<rdfs:label xml:lang="en">station</rdfs:label>
</owl:Class>
<class name="POI">
<geometryType> Point </geometryType>
<description type="definition">Feature
designing street furniture, a place or a zone
having designated as administrative, cultural,
sports, industriel or commercial.</description>
…
</class>
<class name="Toponym for road
networks">
<geometryType> point </geometryType>
<description type="definition">Toponym
feature used as a node of road
network.</description>
…
</class>
translated to English for this presentation
Excerpt of a NMA database
schema defined in XML
Excerpt of a NMA geographic
taxonomy defined in OWL
Module #2: the NMA connector
See Abadie et al. 201012
Context Objectives Proposed Approach Conclusion & Perspectives
13
Module #3: the relationship finder
Bus RouteBus StopIs part of
Context Objectives Proposed Approach Conclusion & Perspectives
14
Module #3: the relationship finder
bus stop
Context Objectives Proposed Approach Conclusion & Perspectives
VGI Feature
Type
NMA Ontology
Concept
Attribute
Type
Proposed Approach
15
Relevant
Relationship
Diagram of the proposed VGI specifications (non-exhaustive)
Geometry
TypeNMA Feature
Type
:: VGI:bus stop
:: NMA:station
:: NMA:point:: NMA:poi
:: NMA:toponym_road_network
:: VGI:zone
:: VGI: …
:: WordNet:(bus_stop, bus_route, part_of)
Context Objectives Proposed Approach Conclusion & Perspectives
Conclusion & Perspectives
• VGI Specifications for usability and quality
• Contribution: method for helping contributors
to build these specifications
• User testing
Reconciliation and evaluation mechanisms:
Formalization of relevant relationships to be
verified as spatial integrity constraints (using the
proposed method, specially the relationships
retrieved)
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Context Objectives Proposed Approach Conclusion & Perspectives
• Thank you for listening!
• Contact information:
• Any questions?
17© IGN - 2011
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