Geocoding in Geographic Information Retrieval Systems

UT-Knoxville Geography Research Symposium 02/22/2014

Tanner JesselSchool of Information Sciences

What is Geocoding?

➲ Geography + Code = Geocode

Place + Space

Assigning geographic coordinates to a recognized location.

Location + Spatial Coordinates

What is Geocoding?

Means different things to different practitioners

Addresses Objects People Animals / Habitats

What is Geocoding?

Sometimes referred to as “Georeferencing” or “Geotagging.”

1955 – 2008 Google “ngram” illustrates trend Interdisciplinary

Geocode (Blue) Georeference (Red)

Interdisciplinary

Georeferencing

Knoxville, Tennessee – what do you think of?

Georeferencing in IR

Knoxville, Tennessee – what Google thinks

Georeferencing in IR

Knoxville, Tennessee – what Bing thinks

Georeferencing in IR

Knoxville, Tennessee – what Bing thinks you think

Georeferencing in IR

➲ How do we answer this question?

What do we mean by “Edinburgh”

What do we consider “near”

Query: what castles are near Edinburgh?

Georeferencing in IR

➲ Which castle? Scotland?

Jamaica?

Georeferencing in IR

➲ What is “near?” 1 km? 3 km? 20 km?

Georeferencing in IR➲ Match text to known “footprint,” or space an

object occupies Castle footprint is known City footprint is known Country footprint is known

Geoparsing

➲ Evaluate the geographic context of an item➲ “Castles near Edinburgh” A physical place Implied location

Edinburgh Scotland United Kingdom Europe

Geoparsing

➲ Possible castle names Craigmillar Castle Edinburgh Castle Lauriston Castle Tantallon Castle Chricton Castle Blackness Castle Dirleton Castle

Gazetteer➲ Links a name to a footprint (point or area)

Gazetteer

➲ Links a name to a footprint (point or area)

Gazetteer

➲ Geographical Index or Dictionary

Ontology for Geo IR

➲ Pragmatic Ontology: how entities can be grouped in a hierarchy

➲ Nation➲ State➲ County➲ City➲ Neighborhood

Ontology for Geo IR

➲ Semantic Ontology➲ words have different meanings to different

groups

“Skin Temperature” of Atmospheric Scientists “Surface Temperature” of Marine Scientists Both are same data point, but mean different things to

different communities of scientists

➲ Technology can handle these differences➲ “Semantic” mediation➲ Applies to spatial domain

Real-World Ontology

Ontology to Computer

Metadata: Machine Friendly

➲ Place➲ Time➲ Geographic Coordinates➲ Geographic Footprint (Area coverage)➲ Relationships Parent Child Similarities

Geographical Information Retrieval System

➲ Spatially Aware➲ Can handle spatial queries Castles

Within 1 KM of Edinburg (Scotland)

Geographical Information Retrieval System

Geographic Information Retrieval System Application

Geocoding Toolkit

➲ Research effort reviewed 53 citations Extracted tools mentioned across citations➲ Categorized tools:

Geographic IR Tools Disambiguation Tools

Georeferencing Tools Error Calculation Tools

Ontology Tools Algorithmic and Programming Tools

Geographic IR Systems Visualization Tools

Database Tools Thesauri ToolsExtraction Tools

Need?

➲ Tools for automation of geocoding / georeferencing

Next Steps

➲ Specialized gazetteers for subject areas are needed These reliably link place to space They enable spatial queries

➲ Specialized ontologies for domain-specific applications are needed These establish relationships between objects in the real and

virtual worlds They enable spatial queries

Questions?