1. Semantic Interoperability GEOG 288MR 24 Apr 2008

2. motivation • definition (Kuhn, ISO TC204) • systems providing and accepting services within and across communities • “negotiated meaning” • componentization of GIS • Lutz, et al: “paradigm shift” to web, distributed? • how prevalent is this? a shift or addition? • are services IR? analytic? wayfinding? • a “technical goal, not a research topic per se”

3. standards mentioned • ISO 19115:2003 • defines the schema required for describing geographic information and services. It provides information about the identification, the extent, the quality, the spatial and temporal schema, spatial reference, and distribution of digital geographic data.

4. ISO 19115:2003

5. OGC standards • WMS: web map service • WFS: web feature service • WPS: “defines a standardized interface that facilitates the publishing of geospatial processes, and the discovery of and binding to those processes by clients.” • Processes include any algorithm, calculation or model that operates on spatially referenced data • Publishing means making available machine-readable binding information as well as human-readable metadata that allows service discovery and use

6. a human process if foo… then bar if foo… then bar matchmaker

8. matchmaking • reasoning about compatibility of offers and requests for data and services: discover, evaluate, combine • by means of ontologies (Kuhn, Lutz et al) • data discovery and evaluation • earlier (Kuhn) “data interoperability…an oxymoron…incoherent” • service discovery and evaluation • service composition • “out there” as a possibility

9. grounding • necessary “grounding conceptions in reality” (Kuhn) • semantic reference systems • the MUSIL project, right? • grounding in • image schemas (next slide) • measurements: all information ultimately rests on observations, made explicit with measurement

10. image schemas (Johnson 1987) • Spatial motion group • Containment • Path • Source-Path-Goal • Blockage • Center-Periphery • Cycle • Cyclic Climax • Force Group • Compulsion • Counterforce • Diversion • Removal of Restraint • Enablement • Attraction • Link • Scale • Balance Group • Axis Balance • Point Balance • Twin-Pan Balance • Equilibrium

11. image schemas

12. Lutz et al framework • 5 levels of explicitness • is level A (“completely implicit”) telepathy? • Hmm… • searching for forest cover in Google? • the ‘examples’ are use scenarios; the scenarios are…process models? use cases?

13. scenario results • scenario 1 • the user must be an expert going in, even then results are iffy • scenario 2 • user makes themselves expert by reading and interpreting metadata • scenario 3 • given a domain ontology, it just works

14. ontology • (Guarino 1998) “an engineering artifact, constituted by a specific vocabulary used to describe a certain reality, plus a set of explicit assumptions regarding the intended meaning of the vocabulary words.” • Specification of a conceptualization • Fonseca, Egenhofer, Agouris and Câmara (2002: 232) “[ontologies are] theories that use a specific vocabulary to describe entities, classes, properties, and functions to a certain view of the world…seen here as dynamic, object-oriented structures that can be navigated." • Required for representation of knowledge(s) AAG Boston :: Grossner

15. CIDOC-CRM(conceptual reference model) CIDOC: working group of International Council of Museums (ICOM); 24,000 members, 150 countries CRM: “General data model for museums, with a particular focus on information interchange” Developed over 10-year period; now ISO 21127:2006 An ontology for cultural heritage information in digital applications for the domains of museums, libraries and archives. Incomplete, but “extensible…continuous need to elaborate new areas” AAG Boston :: Grossner

16. CIDOC-CRM 85 entity class declarations148 property declarations

17. CIDOC-CRM Rudimentary reasoning: property holds for domain of entities, with valid values in range AAG Boston :: Grossner

18. questions • How does the 2007 OGC WPS fit in all this? • is spatial special? (Lutz et al) • it’s all about semantics, after all -- isn’t it? • our symbols are the touchstones (cf. Kuhn figure) • ontologies enable reasoning about types (versus instances in GIS)