Post on 04-Jan-2016
U.S. Department of the InteriorU.S. Geological Survey
A Consideration of Geospatial A Consideration of Geospatial Feature Formation in Linked Feature Formation in Linked Open VocabulariesOpen VocabulariesWorkshop on Linked Open Data: Workshop on Linked Open Data: Activities, Ideas, Practices Activities, Ideas, Practices @ @ GIForum 2014GIForum 2014
Dalia VarankaDalia VarankaJuly 1, 2014July 1, 2014
Geospatial Feature
ISO 19112 Geographic Information – Spatial referencing by geographic identifiers
OGC 11-052r4 OGC GeoSPARQL – A Geographic Query Language for RDF Data
geo:Feature geo:Geometrygeo:hasGeometry
Definitions
Abstraction of real world phenomena (ISO) A digital representation of a real world entity
or an abstraction of the real world (OGC)
Selection of characteristics relevant to an area of interest with disregard of what is irrelevant
Introduction
Concept of a geospatial feature in GIScience literature
Feature class semantics in Linked Open Vocabulary (LOV)
Feature as ontology pattern Hydrography example
Geographical and Cognitive Entities
Features are conceptualized as objects World has fuzzy boundaries Cognitively constructed categories Technical adaptation of the feature concept
Imposes further semantic constraints Must support geographical analysis
Geospatial Feature Concept
Theme
Space Time
Equivalent to a ‘geographical fact’
Berry, B.J.L. 1964. Approaches to Spatial Analysis: A Regional Synthesis. Annals of the Association of American Geographers, 54, 2-11.
Feature Type Class Semantics
Identity
Place (Space)
Time
Attributes
Relations
Usery, E.L., Spatial Feature classes, Encyclopedia of Geography, John Wiley and Sons, In press.
GeoNames Feature Classes (9) and Code Definitions (645)
Geonames Feature Class Semantics
feature class
feature code geonameid name asciiname latitude longitude country code timezone modification date
T PASS 2598245 Sandgatterl Sandgatterl 47.75 14.56667 AT Europe/Vienna 5/2/2014L GRAZ 2598246 Viehtalalm Viehtalalm 47.75 14.56667 AT Europe/Vienna 4/30/1999T CLF 2598247 Adlmoarstein Adlmoarstein 47.75 14.55 AT Europe/Vienna 4/30/1999L GRAZ 2598248 Waldbaueralm Waldbaueralm 47.75 14.56667 AT Europe/Vienna 4/30/1999T PK 2598249 Federeck Federeck 47.75 14.56667 AT Europe/Vienna 5/2/2014P PPL 2598250 Mooshöhe Mooshoehe 47.75 14.55 AT Europe/Vienna 5/2/2014S HUT 2598251 Antonihütte Antonihuette 47.75 14.53333 AT Europe/Vienna 5/2/2014L GRAZ 2598252 Bergeralm Bergeralm 47.75 14.51667 AT Europe/Vienna 4/30/1999L GRAZ 2598253 Blabergalm Blabergalm 47.75 14.5 AT Europe/Vienna 4/30/1999
Feature Semantics in Layer-Based Geographic Information Systems (GIS)
Improved attribute and topological representation
Feature class changed from type to geometry
Feature geometry changed from objects to tabular coordinate pair segments
Feature geometry classes: effective for overlay processing, but not intuitive for feature recognition
Feature Semantics Remedied in Cartography Rich spatial,
thematic, and temporal representation
Web Feature Service (WFS): syntax, but not semantics
Web Ontology Language (OWL)
Hierarchical Class Defined Class
Spatial relationship of features that cross but do not exchange flow
• Subclass of SpatialQuality• Equivalent to crosses min 2
Object• Disjoint with
HydroNetJunction• Domain of
PermenantIdentifier• Domain of
AbovePermenantIdentifier• Domain of
BelowPermenantIdentifier
Feature Pattern Semantics
Identity typeOf
Attribute equivalentTo
Spatial Reference hasGeometry
Temporal Reference Spatial Relations
GeoSPARQL
LOV for U.S. National Hydrography Dataset (NHD)
GIS-NHD Triples From Tables
Subject
PropertyLiteral
Object
Domain ClassesAllowable subjects of a property are limited to a particular table
NHDVerticalRelationship StringAbove_Permanent_Identifier
Surface Water Ontology
NHD Feature Ontology
Instance GazetteerOntology
Mapping and Display
Database Maintenance
Provenance and
Metadata
Cognitive Recognition
Applied Model
Database
NHD Instance (Gazetteer) Classes
Instance Gazetteer
NameGeometry
& Spatial Qualities
Permanent Identifier Hydro_Net
Processes
• Hydro_Net Junction• Flow Direction
• From Permanent Identifier
• To Permanent Identifier
• Point• Line • Area• Elevation• Vertical
Relationship• Relationship
to Surface
• Above Permanent Identifier
• Below Permanent Identifier
• HU Code• TNM ID
Semantic Enhancements: Transitivity
Extensions to segments support inference
Conclusion
Geospatial feature type class semantics worth maintaining in LOV
Feature class modeled as a pattern in LOV LOV object properties support LOD datatype
properties