도로, 철도, 항만과 같은 사회간접자본으로 생산, 유통, 소비 등 경제활동의 기반 투자규모가 크고, 투입된 자본의 회수에 오랜 기일이 소요되며, 효과가 사회전반에 미침 따라서 공공기관이나 정보의 주도에 의해 투자 새로운 서비스 기회를 제공 공간정보와 관련 서비스의 결합
Block • URIs for unambiguous names for resources, • RDF for common data model for expressing metadata, • Ontology(RDFS, OWL) for common vocabularies. Linked Data becomes: Web of data/things/concepts • What is a Thing/Concept? - It can be anything in the world - a movie, a person, a disease, a location… • This page is talking about ‘Barack Obama’, He is a ‘Person’ and he is the ‘President of USA’ ?
as a set of Triples. What is a Triple? Triple in RDF is analogous a sentence in natural language. The form <subject, predicate, object> • Every NL sentence contains 3 parts: subject, predicate & object. Example: • NL Sentence: Obama is the president of USA • RDF Triple: <URI1#Obama> <URI2#presidentOf> <URI3#USA> Adapted from narnirajesh.blogspot.com subject predicate object
An RDF document is best visualized as a graph. Graph notations: • Resources (URI) • Literals (simple values) • Properties Set of triples represented as a graph Adapted from narnirajesh.blogspot.com URI1#Obama URI2#USA 45 URI4#Person
An RDF graph is a logical model, we need to serialize in some format. What serialization Formats does RDF support? • RDF/XML (XML based syntax, popular), NTriple (each triple is represented in one line), Turtle etc. Example: RDF/XML format: <rdf:Description rdf:about=“URI1#Obama"> <rdf:type rdf:resource=“URI4#Person" /> <URI2#isPresidentOf rdf:resource=“URI3#USA" /> </rdf:Description> NTriple format: <URI1#Obama> <URI2#presidentOf> <URI3#USA> <URI1#Obama> < http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < URI4#Person> Adapted from narnirajesh.blogspot.com
a “Web of Data” to connect Distributed Data across the Web The Linking Open Data (LOD) project: http://linkeddata.org/ Translating existing datasets into RDF and linking them together. • For example, DBpedia (Wikipedia) and GeoNames, Freebase, BBC programmes, etc. Government data also available as Linked Data • DATA.gov • DATA.gov.uk
GeoNames.org Dataset Category In- degree dbpedia.org cross-domain 207 geonames.org geographic 141 w3.org cross-domain 117 quitter.se social web 64 status.net social web 63 postblue.info social web 56 skilledtests.com social web 55 reference.data.gov.uk government 45 data.semanticweb.org publications 44 fragdev.com social web 41 lexvo.org cross-domain 37 Datasets with the ten highest indegrees