Geospatial Semantic Web: Is there life after geo:lat and geo:long ? Joshua Lieberman Traverse...
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Transcript of Geospatial Semantic Web: Is there life after geo:lat and geo:long ? Joshua Lieberman Traverse...
Geospatial Semantic Web:Geospatial Semantic Web:Is there life after Is there life after
geo:lat and geo:long ?geo:lat and geo:long ?Joshua Lieberman
Traverse Technologies & Open Geospatial Consortium
European Geoinformatics Workshop, March 2007
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 2
What’s the (Geo) Problem?What’s the (Geo) Problem?
• Special spatial• What is geospatial interoperability?• semantic Web - microformat tagging and (multiple) identity• Semantic Web - (actionable) relationships and triple identity• geosemantic - geotagging position• Geosemantic - spatial(-temporal) theories, relationships,
mediations, transformations• Feature (type) and Geometry (representation)• Model dependencies
– Community of discourse– Scale– Reference frame / coordinate system– Perspective
• Geospatial plus other (semantic) dimensions
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 3
BackgroundBackground
• My context - earth / environmental sciences -> data manager -> Web 1.0 victim -> geospatial standards geek
• What is the geospatial problem, anyway? Is it a geospatial problem? Who needs interoperability?
• Playing fields and players, an arbitrary list:– Open Geospatial Consortium– Worldwide Web Consortium– SOCoP
• “Standards are great, there are so many to choose from”• “OGC is full of semantics, we just don’t let much of it leak
out”• “If there is artificial intelligence, does that mean there is
also artificial stupidity?”
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 4
Geospatial Semantic Web Challenge: Geospatial Semantic Web Challenge: Interoperability Interoperability
• The Geospatial part– Maps and map visualization– Features and feature geometries– Geographic and other relationships– Coordinate and other reference systems
• The Web part– Distributed data - “own and maintain locally / find and access globally”– Shared services, loosely or tightly coupled to geodata– Interoperability between technologies, vendors, architectures
• The Semantic part– Accessibility of “secret” knowledge– Interoperability between communities and domains– Softer software– Automated (machine to machine) reasoning and inference
• The Geosemantic part– Feature discernment– Spatial reasoning– Representational dissonance
• No particular part– Cognitive dissonance– Context and viewpoint
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 5
What are OGC and OWS ?What are OGC and OWS ?
• “The Open Geospatial Consortium, Inc. (OGC) is a non-profit, international, voluntary consensus standards organization that is leading the development of standards for geospatial and location based services”
• “Opengeospatial Web Services” (OWS) - OGC has been developing for some time specifications for a suite of Web services (sensu latu) and associated encodings to expose geospatial content and operations from distributed content repositories to remote clients across diverse platforms:
– GML - geographic markup language (an information model and XML schema) for encoding features (geometric representations of geography).
– Web Feature Service - service providing access to collections of features– Web Map Service - service providing access to map layers (cartographically rendered
features and images)– Catalog Service / Web - service supporting (spatial) discovery of geospatial datasets and
services– Several other associated specifications, e.g. coordinate reference system encoding– Many corresponding or related ISO standards, especially 191nn (TC211)
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 6
General Feature ModelGeneral Feature Model
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 7
Interoperability StackInteroperability Stack
• Meaning - ? (OWL, RDF, MDL, …)
• Vocabulary – UML, XML Schema, OWS
• Encoding - ASCII, UTF-8, XML
• Control – TCP, HTTP, WAP
• Signal – Internet Protocol, DNS
• Transport – Ethernet, WiFi, GPRS
• Medium – Physical Connection
Increasing / higher level interoperability
Human-centric
Machine-centric
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 8
Geospatial R/EvolutionGeospatial R/Evolution
• Geospatial Semantic Web: forming and distributing rich geospatial relationships across the Web
• GeoRSS: adding features to information• Google Earth: the terrain as video game• GeoWeb: connecting features across the
Web• GIS: adding information to features
Cartography: symbolic representation of the terrain
• Geography: perception of the terrain
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 9
Which Geospatial Role?Which Geospatial Role?Tasks /
Pro
cesses
Information Domains
Petro Aero GeoHydro Weather Solar
Collect
Model
Interpret
Visualize
Geog
rap
hic
In
from
ati
on
Syste
m
Common Geospatial Perspective
Upper Ontologies?
Base Ontologies?
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 10
Use cases and roles Use cases and roles for semantic Web processingfor semantic Web processing
• Cross-domain resource discovery• Heterogeneous resource query• Resource translation
Find
Provi
sion
Publish
Order
BindClient Server(s)
Trader
Broker
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 11
““Typical” Geospatial Query Typical” Geospatial Query (Intelligence / Logistics Domain)(Intelligence / Logistics Domain)
“Which airfields within 500 miles of Kandahar support C5A aircraft?”
Aero Feature or Geo Feature?
Buffer or proximity?
Statutory or Nautical?Straight-line or driving?Coordinate system? Afghanistan?
Centroid or outline?
What does this mean to a GIS ?
Feature property or non-spatial information?
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 12
Multiple GSW Ontology ComponentsMultiple GSW Ontology Components
GeoIntelProblem Domain
Ontology
Base Geospatial Ontology(e.g. filter encoding)
Aero Feature Ontologies
(AIXM, DAFIF)
OGC Upper Ontology
(e.g. Feature)
Other Base Ontologies (e.g. measurements)
Other Upper Ontologies
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 13
Which airfields within 80 miles of Banda Aceh support C5A aircraft, i.e. have a runway length >= 12000 ft?
equivalence or subsumption
based on
based on Domain Ontology
Ontological (DL) description of the query concept
Query concept
ID Name Airp_Ident ICAO Elev Type1 Greenville US01357 KZ 00541 A2 Festus Mem US05536 KZ 00433 A
Ontological (DL) description of the application concept “Dafif_Airport”
Application Ontology ConceptJohn Smith
Hybrid Ontology Approach
Logical Reasoning
Ontologies for Enhanced GI DiscoveryOntologies for Enhanced GI Discovery
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 14
OWL-S Service Description OWL-S Service Description Components and QuestionsComponents and Questions
Type of Service
Themes of Content
Provider / business terms
Content Description
Service Bindings / Messages
Bound Parameters
Process and Behavior
Smart Service Consumption
Service Composition
Service Profile
Service Grounding
Service Model
Feature Schema
Content Domain
Feature Individuals
?
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 15
GeoRSS geospatially enabled resource references
Geospatial Ontologies workshops(resource, process, service)
W3C Geospatial Semantic Activities
GSW IE and BeyondGSW IE and Beyond
• The OGC geospatial semantic web interoperability experiment tested initial architectures and technologies for cross-domain, distributed geospatial knowledge query, leading to multiple follow-on activities.
Aero Data (DAFIF) WFS
Aero Data (AIXM) WFS
Geonames Data Gazetteer
Service
DAFIF Ontology
AIXMOntology
GazetteerOntology
Query Domain Ontology
OWL-SDescription
OWL-SDescription
OWL-SDescription
Geospatial Intelligence Query:“Which airfields within 500 miles of
Kandahar support C5A aircraft”
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 16
A Theory of One’s OwnA Theory of One’s Own
• Classical Scientific Method:– Observation -> Hypothesis -> Test
• SWE:– Procedure -> Sensor -> Measurement -> Observation ->
Hypothesis
• John Wesley Powell:– Multiple Hypothesis -> Observation -> Selection
• Practical / Tenure track– Theory -> Procedure -> Measurement -> Observation ->
Publication
• In “reality” observations are always predicated upon a theory, although they may subsequently induce theory revision.
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 17
Problems of heterogeneityProblems of heterogeneity
• Semantics: two names for the same thing• Semiotics: one name for two different things• Schizophrenia (cognitive dissonance): two names for two
different things
LighthouseVertical Obstruction
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 18
Semantic quandariesSemantic quandaries
• Two co-located shapes -> “semantic heterogeneity”• Agree “obstruction” equals “lighthouse” -> boat crashes
into a water tower• Agree lighthouse “is a” vertical obstruction -> ship
ignores light buoy, hits shoal• Agree vertical obstruction “is a” lighthouse -> plane hits
watertower• We have “cognitive heterogeneity” -> two theories for the
same reality
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 19
Unsettling SolutionsUnsettling Solutions
• Possible solution: intersect theories -> lighthouse and vertical obstruction are both “elevations”, but little may be agreed on the role or behavior of that shared reality. Semantic technology provides few tools to distinguish the “theories” of the subclasses.
Vertical Obstruction
Elevation
Lighthouse
Marine Navigation Aid
Aero Hazard
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 20
Top of the Interoperability StackTop of the Interoperability Stack
• Purpose – Enlightenment, tenure
• Perception – Visual - aural - tactile
• Theory - persistence, consequence
• Discernment – Feature, context
• Application – Discovery, analysis, profit
• Representation– geometry, equation
• Ontology – domain, upper, lower
Increasing / higher level interoperability
Human-centric
Machine-centric
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 21
W3C Geo XGW3C Geo XG
• W3C Geospatial Incubator is a new type of activity for short-term and/or startup goals
• The (proposed) Geo XG has three objectives which address needs of the Local Web:– Immediate: update and harmonization with GeoRSS of the W3C Basic
Geo vocabulary, aka simpler than possible geospatial ontology.– Short Term: draft recommendations for a geospatial ontology focused on
Web resources and tasks.– Longer Term: draft a charter for a proposed W3C Local Web WG and/or
IG to address issues beginning with geotags and continuing towards geospatial enablement of the Semantic Web.
• Largely open to public participation• Chartered until June 2007• http://www.w3.org/2005//Incubator/geo/
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 22
W3C 2003 Geo VocabularyW3C 2003 Geo Vocabulary
• Devised and posted by Dan Brickley (danbri)
• Not a Note or Recommendation
• Separate latitude & longitude properties, presumes WGS 84
• Implies a point “feature” and single position.
• Makes no other assertion as to the meaning of the coordinates or their relationship to the item or resource they characterize.
• Geo:lat and geo:long are also used for geotagging other content (e.g. XHTML microformats).
The vocabulary defines a class 'Point', whose members are points. Points can be described using the 'lat' and 'long' properties.
<geo:Point> <geo:lat>55.701</geo:lat> <geo:long>12.552</geo:long> </geo:Point>
In common usage, the containing Point is dropped, for brevity.
<?xml version="1.0"?> <rss version="2.0"
xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#">
<channel>
...
<item> <title>An example annotation</title> <link>http://example.com/geo</link> <description>Just an example</description> <geo:lat>26.58</geo:lat> <geo:long>-97.83</geo:long> </item>
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 23
GeoRSS 1.0 Content “Featurizing” ModelGeoRSS 1.0 Content “Featurizing” Model
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 24
GeoRSS ExamplesGeoRSS Examples
• Simple• <georss:point>45.256
-71.92</georss:point>• <georss:line>45.256 -110.45 46.46 -
109.48 43.84 -109.86</georss:line>• <georss:polygon>• 45.256 -110.45 46.46 -109.48
43.84 -109.86 45.256 -110.45• </georss:polygon>• <georss:box>42.943 -71.032 43.039 -
69.856</georss:box><georss:featuretyeptag>city</georss:featuretypetag><georss:relationshiptag>is-contained-within</georss:relationshiptag>
• GML• <georss:where>• <gml:Point>• <gml:pos>45.256
-71.92</gml:pos>• </gml:Point>• </georss:where>
• <georss:where>• <gml:Polygon>• <gml:exterior>• <gml:LinearRing>• <gml:posList>• 45.256 -110.45 46.46 -109.48
43.84 -109.86 45.256 -110.45• </gml:posList>• </gml:LinearRing>• </gml:exterior>• </gml:Polygon>• </georss:where>
GeoRSS Simple maps directly onto GeoRSS GML !
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 25
SOCoP: SOCoP: Spatial Ontology Community of PracticeSpatial Ontology Community of Practice
• SOCoP is chartered as a Community of Practice under the Best Practices Committee of the Federal CIO Council.
• Charter: The strict purpose and focus of the Spatial Ontology Community of Practice (SOCoP) is to foster collaboration among researchers, technologists & users of spatial knowledge representations and reasoning towards the development of a set of core, common spatial ontologies for use by all in the Semantic Web. As a Community of Practice SOCoP using open collaboration and open standards, SOCoP developed ontologies will offer increased interoperability of spatial data across government (via synchronization with Geospatial Profile of FEA & GeoLOB) as well as across the entire spectrum of the World Wide Web (via W3C, ISO, OGC, etc.). SOCoP represents a strategic investment for ontology development, building on core ontological competencies, documenting best practices, and creating opportunities to partner with other cross domain and ontology COP groups. Among other things SOCoP can help inventory geospatial ontologies, develop an approach to institutionalizing and streamline the effort to support the development and management of ontologies across the GeoLOB.
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 26
Geospatial Semantic Web Standards (?)Geospatial Semantic Web Standards (?)
• Geospatial Ontologies– Neogeo / GeoRSS– Feature metamodel– Feature types– Geonames / toponymology– Spatial relationships– Coordinate reference systems
• Geospatial Semantic Web Services– (Does) content matter?
– Transformation services
– Mediation (semiotic, semantic, cognitive) and client perspective
• Geosemantic Reasoning– Geospatial subsumption
– Processing spatial relationships
– Geospatial rules
– (Geo) SPARQL ?
– Visual reasoning - map and reality
• Geospatial Discovery– Indexing vs modeling
– GeoRSS: geographic assertions over resources
– GRL: Geo resource locator
– GREF: Geo reference
– GNS: Geo Name Server
Joshua Lieberman - European Geoinformatics Workshop 2007 ©Traverse Technologies. Slide 27
Geospatial Semantic ConvergenceGeospatial Semantic Convergence
• When geography-on-demand joins knowledge-with-location, the result will be a richer and more capable Web of physical resources, a Geospatial Semantic Web or Local Web having identity, connection,
and locality
Local
Web
Geographic representation standards
Geospatial Web services architecture standards
Geospatial enablement of enterprise information
Resource identifier and transport standards
Resource relationship standards
Semantic enablement of the World Wide Web
Semantic Web
Web of Knowledge
Information Silos
GIS Guilds Geospatial WebGeospatial Enablement
What do you see is next?What do you see is next?