Christopher Wellen M.Sc. Candidate McGill University On Cognition and Computation: An Introduction to Spatial Ontologies

Agenda ● Ontologies and GIScience ● Historical Antecedents ● Computational Application areas: – Interoperability – Federated Databases ● Cognitive Research – Landscape Categories – Geography as Science ● Critique ● Emergent Debates

What exactly is Ontology? ● Classic answer: “explicit specification of a conceptualization.” (Gruber, 1993) ● Set of entities, attributes, axioms and relations. ● Field encompasses a large part of GIS research ● Geography has no single agreed-upon shared ontology

An Ontology of Streams H. Pundt, Y. Bishr / Computers & Geosciences 28 (2002) 95–102

Suggested Upper Merged Ontology (SUMO) Phytilia, 2002

Top Level vs. Domain Ontologies ● Domain Ontologies: task, specialty, discipline – Bottom-up ● Top Level Ontologies: reality – Top-Down

Cognitive vs. Computational

Why Ontologies? ● Better design of information systems: – Data sharing and data discovery – Data interoperability and machine readability ● More unified geography: – Conceptualize geography at top level

Ontology Development ● Two General strategies for development: – top down – bottom up ● Web-based interfaces: Ontolingua ● Graphical User Interfaces: ConceptVISTA

Ontology Implementation ● Software Components ● Database components ● Data collection policies

Great Britain Historical GIS – Ontology of Administrative Boundaries Contains Dates of Creation/ Abolition Geometry Stats Contains Relationship Classes

Historical Antecedents ● Philosophy – Aristotle – Smith and Mark (1998) – geographical domain does not divide into bounded concepts neatly ● Information Science/Artificial Intelligence – Gruber (1993) – re-usable software components ● Semantic Web – World Wide Web Consortium (W3C) wants to make web machine-readable

Computational Applications ● Interoperability - FieldLog ● Federated Databases - GeoNIS

Interoperability - FieldLog (Broderic 2004) Scientists like to invent their own language Government database managers like everyone to use the same language Major conflict in Geological Survey of Canada, which has both types of people Solution: FieldLog

Top level classes Cartogra phic Geospati al Metadata Geologic Symbolization Coordinates Geologic concepts and analysis References and documentation StationRockSampleAnalysis Drill Hole ID Lat Lon A Site ID Lat Lon A01 1 granite Lithology Site Rock Type A01 1 A Sample Site Rock Sample A01 1 A Geochem Site Rock Sample User defined classes User defined classes User data User data

FieldLog User profiles can be created and edited Maps can be generated quickly and with minimal complaining (hopefully...)

Federated Databases DB2 Middleware DB1 User

Federated Databases

Federated Databases - GeoNIS ● Each user describes their data in terms of a common ontology ● Requests for others' data can be phrased in terms of one's own ontology ● Translators can translate the request for data into others' ontologies as well as their data into the ontology of the user who requested the data

Federated Databases - GeoNIS ● ‘Top-Level’ ontology: Open Geospatial Consortium – data model standard for geospatial data ● Users use relations: synonym (same thing), hypernym (superclass), hyponym (subclass), Topology ● Topology: arc-node, route, NodeRoute, point- event

(Stoimenov and Djordjevic-Kajan 2005)

Cognitive Work ● How do people concieve of/categorize space/spatial features? ● Landscape Categories: – Do mountains exist? – Yindjibarndi (Mark and Turk, 2003)

Critiques ● Little work that synthesizes whole spectrum – mostly cognitive or computational ● Used as a buzzword to give research more exposure ● Formal ontologies seen as a technical exercise, little work done to explore cultural/power differences. ● Ontologies seen as too complicated (Schuurmann) ● What about fuzzy boundaries?

Emergent debates ● Top level ontology? What would it look like? Can everyone agree on it? ● Should Ontology development proceed from a top-down or bottom up manner? ● Can Spatial Ontologies be produced independently of temporal ones?

What is not quite Ontology? ● Semantics – Methods of representing knowledge (from harvey’s data sharing paper) – Does not describe relations between features or what they actually are ● Taxonomy – Classification is not conception. ● Folksonomy – Flickr photos, messy taxonomy