20130905_Feng_Chia_GIS_center_geospatial_ontology
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    20130905_Feng_Chia_GIS_center_geospatial_ontology 20130905_Feng_Chia_GIS_center_geospatial_ontology Presentation Transcript

    • 1 Geo-Ontology and -Semantics: From Theoretics to Practices Institute of Information Science, Academia Sinica Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente Dongpo Deng dongpo.deng@gmail.com Tuesday, September 10, 2013
    • What is ‘O’ntology? • The term originated from a philosophical discipline • A branch of philosophy that deals with the nature and the organization of reality • It was defined by Aristotle in Metaphysics, IV, 1 • It tries to answer the questions: • What is being? • What are the features common to all beings? • How should things be classified? 2 Tuesday, September 10, 2013
    • What is ‘o’ntology? • a specification of a conceptualization (Gruber, T. 1993) • a formal specification of a shared conceptualization (Borst et al., 1997) • is a hierarchically structured set of terms for describing a domain that can be used as a skeletal foundation for knowledge base (Swartout et al., 1996) • the method to extract a catalogue of things or entities (C) that exist in a domain (D) from the perspective of a person who use a certain language (L) to describe it (Sowa, 2000) 3 Tuesday, September 10, 2013
    • What is ‘o’ntology? • From AI perspective (Agarwal, 2005) • “conceptualization” is explained as an abstract model of some phenomenon in the world by having identified the relevant concepts of that phenomenon. • “explicit” means that type of concepts used and the constraints on their use are explicitly defined • “formal” refers to the fact that the ontology should be machine- readable • “shared” refers to notion that on ontology captures consensual knowledge 4 Tuesday, September 10, 2013
    • An example of ontology description • Example Vocabulary and meaning (“definitions”) • A ‘Carnivore’ is a concept whose members are exactly those animals who eat only meat • A ‘Bear’ is a concept whose members are a kind of ‘Carnivore’ • A ‘Cub’ is a concept whose members are exactly those ‘Bear’ whose age is less than one year • A Panda is a individual of a ‘Bear’ 5 Tuesday, September 10, 2013
    • An example of ontology description • Background knowledge/constraints on the domain (“general axioms”) • No individuals can be both a Herbivore and a ‘Carnivore’ • Each ‘Bear’ has a period of ‘Cub’ • The age of adult ‘Bears’ is at least 1 year old 6 Tuesday, September 10, 2013
    • The meaning triangle 7 Tuesday, September 10, 2013
    • Syntax-Semantics-Pragmatics • Syntax (語法) deals with the study of relationships between symbols • Semantics (語意) analyzes the relationships between symbols and things in the real world they denote (referent) • Pragmatics (語用) goes beyond syntax and semantics, and researches how symbols are used for particular purposes. Thus, is analyzes relationships between symbols and specific agents 8 Tuesday, September 10, 2013
    • Ontologies for communication Adapted by Maedche, 2001 9 Tuesday, September 10, 2013
    • Ontology in Computer Science • An ontology refers to an engineering artifact consisting of: • A vocabulary used to describe (a particular view of) some domain • An explicit specification of the intended meaning of the vocabulary • almost always includes how concepts should be classified • Constraints capturing additional knowledge about the domain • Ideally, an ontology should: • Capture a shared understanding of a domain of interest • Provide a formal and machine manipulable model of the domain 10 Tuesday, September 10, 2013
    • Why develop ontology? • To share common understanding of the structure of information among people or software agents • To enable reuse of domain knowledge • To make domain assumptions explicit • To separate domain knowledge from the operational knowledge • To analyze domain knowledge 11 Tuesday, September 10, 2013
    • Ontology spectrum Logical Theory Conceptual Model Thesaurus Taxonomy is Disjoint Subclass of with Transitivity property is Subclass of has Narrower meaning then is Sub-Classification of Model Logic First Order Logic Description Logic DAML_OIL, OWL UML RDF/S XTM Extended ER ER DB Schemas, XML Schema Relational Model, XML strong semantics weak semantics Semantic Interoperability Structure Interoperability Semantic Interoperability Syntactic Interoperability 12 Tuesday, September 10, 2013
    • 物種分類名錄 (taibif.tw) 13 Tuesday, September 10, 2013
    • OpenStreetMap Map Features 14 Tuesday, September 10, 2013
    • ADL Gazetteer Feature types From http://www.alexandria.ucsb.edu/~lhill/ FeatureTypes/ver070302/00000250.htm 15 ADL Gazetteer Feature types Tuesday, September 10, 2013
    • From http://wordnetweb.princeton.edu/ 16 Tuesday, September 10, 2013
    • 17 The application ontology inheriting GeoSPARQL Tuesday, September 10, 2013
    • Edited by Protege 18 Tuesday, September 10, 2013
    • 19 Tuesday, September 10, 2013
    • Different kinds of ontologies and their relationships top-level ontology very general concepts, e.g. toopology, mereology, geometry, ... vocabularies related to a generic domain by specializing the top-level ontologies, e.g. GeoSPARQL domain ontology task ontology application ontology vocabularies related to a generic task or activity by specializing the top-level ontologies, e.g. Semantic Sensor Network (SSN) ontology concepts inheriting domain or task ontologies for supporting in certain activities, e.g. we use SSN and GeoSPARQL to create an ontology for ecological observation 20 Tuesday, September 10, 2013
    • Courtesy: Pascal Hitzler, GeoSemantics, 2009 Description Logics Tuesday, September 10, 2013
    • Courtesy: Pascal Hitzler, GeoSemantics, 2009 Ontology and reasoning Tuesday, September 10, 2013
    • Courtesy: Pascal Hitzler, GeoSemantics, 2009 Ontology and reasoning Tuesday, September 10, 2013
    • Courtesy: Pascal Hitzler, GeoSemantics, 2009 Ontology and reasoning Tuesday, September 10, 2013
    • Courtesy: Pascal Hitzler, GeoSemantics, 2009 Ontology and reasoning Tuesday, September 10, 2013
    • Courtesy: Pascal Hitzler, GeoSemantics, 2009 Ontology and reasoning Tuesday, September 10, 2013
    • Courtesy: Pascal Hitzler, GeoSemantics, 2009 Ontology and reasoning Tuesday, September 10, 2013
    • What’s the (Geo) Problem? • What’s special about Spatial? • spatial-time-attributes • What is geospatial interoperability? • GML? WFS? or more alternatives? • semantic Web - microformat tagging and (multiple) identity • Semantic Web - (actionable) relationships and triple identity • geosemantic - geotagging position • Geosemantic - spatial(-temporal) theories, relationships, mediations, transformations 28 Adapted from J. Lieberman (2007) Geospatial Semantic Web: Is there life after geo:lat and geo:long ? Tuesday, September 10, 2013
    • What’s the (Geo) Problem? • Feature (type) and Geometry (representation) • Model dependencies • Community of discourse • Scale • Reference frame / coordinate system • Perspective • Geospatial plus other (semantic) dimensions 29 Tuesday, September 10, 2013
    • Two approaches for studying on geo ontologies • There are two distinct approaches that applied ontology in GIScience. • The philosophical approaches aim to identify specifications of top-level categories from a formal ontology perspective, • The domain-specific and task-oriented approaches focus on explicating the actions, terms and relation for particular specification and ranging from natural language to rigorously formal specifications. 30 Tuesday, September 10, 2013
    • How difficult to develop geospatial ontology? • Geographic objects are typically complex, and they will in every case have parts. (Simons, 1987; Smith and Mark, 1998) • The geographic domain has specific issues regarding ontology primarily because of its unstructured characteristics • A standard terminology is not prevalent within the GIScience domain and is dependent on the context of use and the user • causes confusion in specification of universally accepted entities, concepts, rules, relation, and semantics as the basis of a consensual ontology. 31 Tuesday, September 10, 2013
    • Geographical Entities are Indeterminate and Ambiguous Objects Philosophically speaking: Where does the mountain begin and the valley end? How can we derive a common semantics which can refer accurately to these kinds of objects? B. Smith and D. Mark, 2003. Do Mountains Exist? Towards an Ontology of Landforms. Environment and Planning B, 30(3), 411-427 32 Tuesday, September 10, 2013
    • Geographical Entities are Indeterminate and Ambiguous Objects Philosophically speaking: Where does the mountain begin and the valley end? How can we derive a common semantics which can refer accurately to these kinds of objects? B. Smith and D. Mark, 2003. Do Mountains Exist? Towards an Ontology of Landforms. Environment and Planning B, 30(3), 411-427 32 Tuesday, September 10, 2013
    • Geospatial objects: vagueness and ambiguity • Geographic categorization and classification are scale- and size-dependent, • regionalization in space and time is human-dependent, and location and structure of boundaries shape many geographical categories. • The ways that space and time determine relations and property inheritance are not yet clear. • Human dependence means that geographic categories and nomenclature can have different meanings in different application contexts. • fiat (tennis court) and bona fide (shoreline or riverbanks) • open (bay) and closed (lake) 33 B. Smith and D. Mark, 2003. Do Mountains Exist? Towards an Ontology of Landforms. Environment and Planning B, 30(3), 411-427 Tuesday, September 10, 2013
    • Conceptual model in General Feature Model (GFM) 34 Tuesday, September 10, 2013
    • W3C Basic Geo Vocabulary 35http://www.w3.org/2003/01/geo/ Tuesday, September 10, 2013
    • Map4RDF 36 http://oeg-dev.dia.fi.upm.es/map4rdf/ Tuesday, September 10, 2013
    • Geonames.org 37 http://www.geonames.org/maps/google_25.048_121.532.html Tuesday, September 10, 2013
    • ‘Taipei’ in Geonames 38 http://sws.geonames.org/1668341/about.rdf Tuesday, September 10, 2013
    • Geonames ontology 39 http://lov.okfn.org/dataset/lov/details/vocabulary_gn.html Tuesday, September 10, 2013
    • Ordnance survey Ontologies 40 http://data.ordnancesurvey.co.uk/ontology/ Tuesday, September 10, 2013
    • Spatial Relations in OS ontologies 41 http://data.ordnancesurvey.co.uk/ontology/spatialrelations/contains Tuesday, September 10, 2013
    • Spatial Relations in OS ontologies 42 http://data.ordnancesurvey.co.uk/ontology/spatialrelations/contains.ttl Tuesday, September 10, 2013
    • GeoSPARQL • The GeoSPARQL will be a new OGC standard, which provides three main components for encoding geographic information: • (1) The definitions of vocabularies for representing features, geometries, and their relationships; • (2) A set of domain-specific, spatial functions for use in SPARQL queries; • (3) A set of query transformation rules 43 Robert Battle, Dave Kolas, 2011. Enabling the Geospatial Semantic Web with Parliament and GeoSPARQL Tuesday, September 10, 2013
    • Components of GeoSPARQL • Vocabulary for Query Patterns • Classes • Spatial Object, Feature, Geometry • Properties • Topological relations • Links between features and geometries • Datatypes for geometry literals • ogc:wktLiteral, ogc:gmlLiteral • Query Functions • Topological relations, distance, buffer, intersection, … • Entailment Components • RDFS entailment • RIF rules to compute topological relations 44 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Vocabulary: Basic Classes and Relations 45 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Details of ogc:wktLiteral 46 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Details of ogc:gmlLiteral 47 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Topological Relations between ogc:SpatialObject 48 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • RCC8, Egenhofer & Simple Features 49 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Example Data 50 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Why Encode Geometry Data as a Literal? 51 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Why don’t GeoSPARQL support W3C Basic Geo? • Too simple to meet our requirements • Can’t use different datums and coordinate systems • Limited number of geometry types • W3C Basic Geo data can easily be converted to wktLiteral 52 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Query Functions 53 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Query Functions 54 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Query Functions 55 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Query Functions 56 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Topological Query Functions 57 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Topological Query Functions 58 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Example Query 59 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL RDFS Entailment Extension 60 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Simple Features Geometry Types 61 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Query Rewrite Extension 62 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • GeoSPARQL Query Rewrite Extension 63 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Query Rewrite Rules • Used to compute Feature-Feature spatial relations basedon default geometries • Specified as a collection of RIF rules • Example: ogcr:sfEquals 64 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Summary of Conformance Classes • Parameters • Serialization • WKT • GML • Relation Family • Simple Features • RCC8 • Egenhofer 65 Determines geometry classes and geometry literal datatype Determines topology properties and topology functions Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • Why don’t you support W3C Basic Geo? • Too simple to meet our requirements • Can’t use different datums and coordinate systems • Limited number of geometry types • W3C Basic Geo data can easily be converted to wktLiteral 66 Courtesy from M. Perry (2012)The GeoSPARQL OGC Standard, Terra Cognita. Tuesday, September 10, 2013
    • BBN Parliament 67 Tuesday, September 10, 2013
    • 68 Tuesday, September 10, 2013
    • An example query of GeoSPARQL(1) • Within 69 SELECT DISTINCT ?POO ?POO_wkt WHERE { ?POO a eoe:PointOfObservation; geo:hasGeometry ?POO_geo. ?POO_geo geo:asWKT ?POO_wkt. FILTER (geof:sfWithin(?POO_wkt, "Polygon ((121 22, 121 23, 122 23, 122 22, 121 22))"^^sf:wktLiteral)) } Tuesday, September 10, 2013
    • Query results (1) 70 Tuesday, September 10, 2013
    • An example query of GeoSPARQ(2) • buffer and within 71 SELECT DISTINCT ?p_wkt?POO_wkt ?distance WHERE { ?POO a eoe:PointOfObservation; geo:hasGeometry ?POO_geo. ?POO_geo geo:asWKT ?POO_wkt. geo:point_238918712815615_43904355280312 9 geo:asWKT ?p_wkt; LET (?buff := geof:buffer(?p_wkt, 3000, units:metre)) . FILTER (geof:sfWithin(?POO_wkt, ?buff)) . LET (?distance := geof:distance(?POO_wkt, ? p_wkt, units:metre)) } Tuesday, September 10, 2013
    • Query results (2) 72 Tuesday, September 10, 2013
    • Q&A 73 Tuesday, September 10, 2013