Download - Georeferencing: Theory and Challenges
Georeferencing:Theory and Challenges
Dr Michael RigbyAAH-DARIAH-ARDCThursday 28 March Knowledge Exchange Session 2 GeoHumanities
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Entities
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ST Representation
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GIScience is an information science(Kemp, 2008)
Refers to the scientific study of geographic information (GI)
Requires understanding of▪ Fields of inquiry▪ Knowledge creation methods▪ Shared expertise across fields
(Duckham, 2017)
Information science
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Perspectives
EpistemologyTeleology
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Definition:
The linking between an entity and a spatial footprint
Entity must have spatial grounding
Georeferencing
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Georeferencing process
Input
Reference data
ParsingFeature
MatchingFeature
InterpolationOutput
General components (Goldberg, 2017)
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1. TextCharactera) Structured (e.g. address)b) Unstructured (e.g. toponym)
Integerc) Structured (e.g. joining IDs)
2. Rasterd) Grid (e.g. image transformation)
Example input
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a) Address geocoding
Assigning an address a spatial footprint
Input: Text (char, structured)
Example: “64 Lincoln Ave Melbourne Australia”
Goldberg, Wilson, and Knoblock (2007); Hill (2006)
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a) Address geocoding
Reference data:▪ Address file
▪ G-NAF Live ▪ G-NAF Open (3 months)
Feature Matching
Reference data
https://www.psma.com.au/products/g-naf
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a) Example geocoding levels
“64 Lincoln Ave Melbourne Australia”
“Lincoln Ave Melbourne Australia”
“Melbourne Australia”
“Australia”
Point
Line
Polygon
Polygon
Address Input Geocoding Output
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But existing tools are a black box
GoogleBingMapboxPSMAGisgraphyHEREGeocode.xyzLocationIQTomtomGeocode.farmYahoo BOSSgeocode.earthSmartyStreets…
Feature matching algorithm?Reference datasets?
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Repurposing / Tool Making
Digital methods –
How do we know that one approach is appropriate for another’s purpose?
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Example gazetteer
Observatory Hill, SA
How might this place be represented?
What else might we need to consider?
Location vs place
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b) Toponym resolution
Assigning a toponym (place name) a spatial footprint
Input: Text (char, unstructured)
Example: “Lake Macquarie”
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b) Toponym resolution
Input ParsingFeature
MatchingFeature
InterpolationOutput
Adapted from Goldberg (2017)
Training Corpora
NERAmbiguity Resolution
Reference data
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b) Toponym examplePlace description: NSW 1881 CensusSource: http://hccda.ada.edu.au/
Country?
Admin or Topographic?
Topographic?
tinker.edu.au
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b) Toponym resolution
Reference data:▪ Gazetteers
▪ National (e.g. GA)▪ State (e.g. VICNAMES)
▪ Other▪ GeoNames (http://www.geonames.org/)▪ DBpedia (https://wiki.dbpedia.org/)▪ ANPS (http://www.anps.org.au/)▪ …
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Multiple candidates“Lake Macquarie” – “Awaba”
http://www.geonames.org/search.html?q=lake+macquarie&country=AU
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What ST representation?
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Ambiguity resolution ST
The process of identifying a single spatial footprint from multiple candidates
This process can be assisted using:▪ Confidence scores▪ Ontologies▪ ST extents▪ Previous research (feedback)
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NER and chunking
Context is critical
“Lake Macquarie”
Topological relations
“Kahibah at the entrance of … Lake Macquarie … thence by”
Places can change…The Electoral District of Kahibah was created in 1894 … It was abolished in 1920 with the introduction of proportional representation. It was recreated in 1927.It was abolished and partly replaced by Waratah in 1930. It was recreated in 1950It was abolished again in 1971 and replaced by Charlestown.
Source: DBpedia.org
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Sands & McDougall Directories
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Yellow Pages
Source: http://www.abc.net.au/news
Historical challenges
What about bias?
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External world knowledge cannot be derived from linguistic principles alone
Leidner (2017)
Note
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Thought experiment
Imagine we had a complete repository of
reference data
for the entire world…
for all time…
Could we identify a location?
Could we identify a place?
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c) Joining IDsSo
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ABS SA2 Boundaries 2016
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d) Image transformation
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Funding for AURIN has been provided by the Australian Government under the National Collaborative Research Infrastructure Strategy (NCRIS) and associated programmes.
AURIN Administrative OfficeThomas Cherry BuildingCorner Swanston and Elgin Street, Carlton(entrance through Level 2, McCoy Building, The University of Melbourne VIC 3010T: +61 3 8344 3212E: [email protected]
@aurin_org_au
Thank you
Steve Bennett, Steve McEachern, Steve Cassidy, Rob Hutton and members of the HASS DeVL team
Contact:
Dr Michael RigbyAURIN, The University of [email protected]