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

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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

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Wikipedia policy on external sources citation in articles http://en.wikipedia.org/wiki/Wikipedia:Citing_sources

Context Objectives Proposed Approach Conclusion & Perspectives

Context: Wikipedia

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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)

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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

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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

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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

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Module #3: the relationship finder

Bus RouteBus StopIs part of

Context Objectives Proposed Approach Conclusion & Perspectives

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Module #3: the relationship finder

bus stop

Context Objectives Proposed Approach Conclusion & Perspectives

VGI Feature

Type

NMA Ontology

Concept

Attribute

Type

Proposed Approach

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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:

• carmen.brando-escobar@ign.fr

• benedicte.bucher@ign.fr

• Nathalie-f.abadie@ign.fr

• Any questions?

17© IGN - 2011