1 / 10

Representation and querying of linked geospatial data- tutorial

Representation and querying of linked geospatial data- tutorial. Konstantina Bereta 10/02/2014. Example in stRDF. gag:Olympia gag:name "Ancient Olympia "; rdf:type gag:MunicipalCommunity . Spatial literal.

glen
Download Presentation

Representation and querying of linked geospatial data- tutorial

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Representation and querying of linked geospatial data- tutorial KonstantinaBereta 10/02/2014

  2. Example in stRDF gag:Olympia gag:name"Ancient Olympia"; rdf:typegag:MunicipalCommunity . Spatial literal gag:Olympiagag:geometry "POLYGON((21.5 18.5, 23.5 18.5, 23.5 21, 21.5 21, 21.5 18.5)); <http://www.opengis.net/def/crs/EPSG/0/4326>"^^ strdf:WKT . Spatial data type 2

  3. Example in GeoSPARQL gag:Olympia rdf:typegag:MunicipalCommunity; gag:name"Ancient Olympia"; gag:population"184"^^xsd:int; geo:hasGeometryex:polygon1. ex:polygon1 rdf:typegeo:Geometry; geo:asWKT "POLYGON((21.5 18.5,23.5 18.5, 23.5 21,21.5 21,21.5 18.5)) "^^sf:wktLiteral. Property from Geometry extension Spatial literal Spatial data type 3

  4. stSPARQL: Geospatial SPARQL 1.1 • We define a SPARQL extension function for each function defined in the OpenGIS Simple Features Access standard • Basic functions • Get a property of a geometry • xsd:intstrdf:dimension(strdf:geometry A) • xsd:stringstrdf:geometryType(strdf:geometryA) • xsd:intstrdf:srid(strdf:geometry A) • Get the desired representation of a geometry • xsd:stringstrdf:asText(strdf:geometryA) • xsd:stringstrdf:asGML(strdf:geometryA) • Test whether a certain condition holds • xsd:booleanstrdf:isEmpty(strdf:geometryA) • xsd:booleanstrdf:isSimple(strdf:geometryA) 4

  5. stSPARQL: Geospatial SPARQL 1.1 • Functions for testing topological spatial relationships • OGC Simple Features Access • xsd:booleanstrdf:equals(strdf:geometryA, strdf:geometry B) • xsd:booleanstrdf:disjoint(strdf:geometryA, strdf:geometry B) • xsd:booleanstrdf:intersects(strdf:geometryA, strdf:geometry B) • xsd:booleanstrdf:touches(strdf:geometryA, strdf:geometry B) • xsd:booleanstrdf:crosses(strdf:geometryA, strdf:geometry B) • xsd:booleanstrdf:within(strdf:geometryA, strdf:geometry B) • xsd:booleanstrdf:contains(strdf:geometryA, strdf:geometry B) • xsd:booleanstrdf:overlaps(strdf:geometryA, strdf:geometry B) • xsd:booleanstrdf:relate(strdf:geometryA, strdf:geometry B, • xsd:stringintersectionPatternMatrix) • Egenhofer • RCC-8 5

  6. stSPARQL: Geospatial SPARQL 1.1 • Spatial analysis functions • Construct new geometric objects from existing geometric objects • strdf:geometrystrdf:boundary(strdf:geometry A) • strdf:geometrystrdf:envelope(strdf:geometry A) • strdf:geometrystrdf:convexHull(strdf:geometry A) • strdf:geometrystrdf:intersection(strdf:geometry A, strdf:geometry B) • strdf:geometrystrdf:union(strdf:geometry A, strdf:geometry B) • strdf:geometrystrdf:difference(strdf:geometry A, strdf:geometry B) • strdf:geometrystrdf:symDifference(strdf:geometry A, strdf:geometry B) • strdf:geometrystrdf:buffer(strdf:geometry A, xsd:double distance, xsd:anyURI units) • Spatial metric functions • xsd:floatstrdf:distance(strdf:geometry A, strdf:geometry B, xsd:anyURI units) • xsd:floatstrdf:area(strdf:geometry A) • Spatial aggregate functions • strdf:geometrystrdf:union(set of strdf:geometry A) • strdf:geometrystrdf:intersection(set of strdf:geometry A) • strdf:geometrystrdf:extent(set of strdf:geometryA) 6

  7. GeoSPARQL Topology Vocabulary Extension • The extension is parameterized by the family of topological relations supported. • Topological relations for simple features • The Egenhofer relations e.g., geo:ehMeet • The RCC-8 relations e.g., geo:rcc8ec 7

  8. The system Strabon • Data model: stRDF • Query language: stSPARQL/GeoSPARQL • Use of OGC standards(Well-Known Text and GML) 8

  9. The system Strabon (cont’d) WKT GML [ ISWC 2012 ] stRDFgraphs stSPARQL/ GeoSPARQL queries 9

  10. links • Strabon endpoint installation guide • Strabonwebsite • stSPARQLreference • Greek Linked Open Data datasets

More Related