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