specifications for user generated spatial content
DESCRIPTION
My presentation at the International Conference on Geographic Information Science AGILE 2011, held at Utrecht University, The Netherlands.TRANSCRIPT
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
5
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
11
{{ 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)
16
Context Objectives Proposed Approach Conclusion & Perspectives
• Thank you for listening!
• Contact information:
• Any questions?
17© IGN - 2011