geoXwalk:-

Developing a Gazetteer Service and Server for UK Academia

James S ReidProject Manager, Geo-data Services, EDINA

AGILE Conference 2003Lyon

Context - EDINA

• a JISC National Data Centre, 1995 -– hosted by Edinburgh University Data Library, 1984 -

• mission... to enhance productivity of research, learning and teaching in UK higher & further education

• major provider within the JISC Information Environment– range of bibliographic resources– multimedia and image services– key geo-spatial data and geo-referenced information

• UKBORDERS (1994 - ) boundary outlines & geo- reference database• Digimap (2000 -) online source of Ordnance Survey mapping

– development projects - geoXwalk,Go-Geo!,e-MapScholar,Pathfinder...

• strategic move toward interoperability & shared services role – adoption of appropriate standards (OGC,ISO)

Context - The JISC Information Environment is…

• variously stated as …– a national digital library... for UK higher and further education– a managed collection of quality assured resources– a distributed resource supporting learning and research in the

UK

• definitely heterogeneous– ‘words, numbers, pictures, sound’: including geo-spatial data

• for use by researchers, students, teachers & support staff • based on an underlying functional model

– simplified to: search -> obtain -> use -> publish– {discover/locate} {request/access} {view/copy/amend/combine}

{publish}

• now to have location-based searching– requiring geo-referencing of information objects

Gazetteer - A list of geographic features together with their associated spatial location

Digital Gazetteer - An electronic list of geographic features together with their associated spatial location

An authority database of places (and features?)An ‘Active Gazetteer”

Digital Gazetteer Service - A network-addressable middle-ware server supporting geographic referencing and searching.

A shared ‘terminology’ service.

Definitions

The problem

How to search ‘geographically’ ? given that : e.g. a postcode, a placename and an administrative area are all valid

geographies and yet every information system cannot know about all the possible variations of what constitutes a ‘geography’!

Problem compounded by inconsistency of use even in the ‘standards’ e.g. placenames evolve, have alternative names

Long history in UK of boundary changes and changes in the geographies used to record things e.g. electoral ward boundary changes …

There is underlying complexity, such as Multiple Geographies …

The vision

How?

A digital gazetteer that stores the different geographies and can implicitly resolve the relationships between them

Provision as a service to service other services

Make variations in defn. of ‘geography’ transparent

Provide a means to ‘crosswalk’ geographies i.e. translate one geography into another - hence the name

‘Geographic agnosticism’

Results of scoping study (Phase I)

Great deal of interest both within and without academia in concept of a digital gazetteer

Such a gazetteer would act as an important reference source

The gazetteer could also support machine to machine (m2m) interactions based on open protocols making it capable of becoming a ‘shared service’

A suitably extensible model for the gazetteer was identified in the Alexandria Digital Library (ADL) model

A prototype demonstrator gazetteer should be developed based on the ADL model

Phase II - Project Aims

To develop a ‘proof-of-concept’ geo-spatial gazetteer service suitable for extension to full service and illustrating: The use of a gazetteer to enhance the geographic searching of

one or more existing JISC services The use of a gazetteer to assist in the semi-automatic geographic

indexing of descriptions of JISC resources Reference use through the provision of a command driven web-

based interface, to show the types of queries that could be answered by a well-populated service

To consider how the gazetteer data could be made available as a shared service as part of the JISC Information Environment

Promote the possibilities of a fully functioning service

geoXwalk - High Level Architecture

The geoXwalkServer

(Spatially enabled RDBMs)

Web client

Request via protocol(ADL, OGC, Z39.50)

Information server

Request via protocol(ADL, OGC, Z39.50)

(human interaction)(machine2machine interaction)

ADL Gazetteer Content Standard

Geographic Feature ID Geographic Name Variant Geographic Name (R) Type of Geographic Feature (R) Other Classification Terms (R) Geographic Feature Code (R) Spatial Location (R) Street Address Related Feature (R) Description Geographic Feature Data (R) Link to Related Source of Information (R) Supplemental Note

Metadata Information

http://www.alexandria.ucsb.edu/gazetteer

• comprehensive description but with small set of core elements• temporal aspects of names, footprints, relationships, …• document source, spatial accuracy/scale of footprint• does permit explicit relationship types!

Gazetteer Database

• Built on ADL Content Standard• Currently seeded with:

– OS 1:50,000 digital Gazetteer – digital boundary data from UKBORDERS– data sourced from other OS products - Strategi, Meridian,

1:250,000 gazetteer– starting to add 3rd party data including Getty

• Accuracy enhanced and metadata support• Current coverage:

– Geographical - GB– Thematic - see below

geoXwalk gazetteer - current thematic content

(based on adapted ADL Feature Type Thesaurus)

Protocols

• ADL Query Protocol– lightweight, generic, relatively simple to implement

• OGC Filter Encoding Specification– fuller, highly flexible, more complex

• Z39.50– pervasive in JISC IE, not specifically for geo-spatial data,

lack of support

• identifier-query identifier Return gazetteer entry identified by identifierSupported by geoXwalk

• name-query operator text Returns gazetteer entries which match text under text-operator operator geoXwalk supports the mandatory equals operator and the optional match-pattern operator

• footprint-query operator (polygon | box | identifier)Returns all gazetteer entries having a footprint that matches a query region according to spatial operator operatorgeoXwalk supports spatial operators within, contains and overlaps. Spatial extents can be specified by bounding box or identifier.

5 types of ADL query:

ADL queries (contd)

• class-query thesaurus term

Returns all gazetteer entries which belong to the class (feature type).

geoXwalk supports class queries (but currently does not return sub-classes by default as the ADL does)

• relationship-query relationship identifier

Returns all gazetteer entries having relationship relationship to a target gazetteer entry identified by identifier.

geoXwalk does not support queries of this type because we do not hold explicit relationships between entities - they are derived implicitly from the geometries

Reference use

Information server

Information server

Searching (1)

Geo-parsing &indexing

The geoXwalkServer

geoXwalk use cases

Searching (2)

e.g.•Where is Aberdour?•On what river is Dundee situated?•By what alternative names has York been known?•List me all places ending with ‘kirk’

Contact details

• James.Reid@ed.ac.uk

• For EDINA services contact: http://edina.ac.ukEDINA, Data Library, University of Edinburghedina@ed.ac.uk or telephone +44 (0)131 650 3302

• For information on geoXwalk project:www.geoXwalk.ac.uk

Task: Find resource about 'Liverpool docks’Search using a ‘traditional’ gazetteer might yield:

… that means more & better hits …. !!!

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Using spatial proximity in an active gazetteer, the search can be widened:

Place County/UALiverpool Liverpool

Bebbington Wirral

Birkenhead Wirral

Bootle Sefton

New Brighton Wirral

Seacombe Wirral

Seaforth Wirral

Waterloo Sefton

co-ordinates allow (near) co-located places to be co-identified.

geoXwalk use case : simple cross searching

geoXwalkServer

Content Provider C

ContentProvider A

ContentProvider B

Coordinate footprints

Parish names

Place names

Portal service

Post code: L34 0HS?

‘Find resources for this postcode’ (NB postcode often used to geo-reference survey data files)

Knowsley

340900,392300 - 347217, 397660

BX003

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geoXwalk use case :(semi) automatic indexing

Need screen shot of parser here

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Objectives (1)

Elicit the detailed requirements for a gazetteer service Involve organisations outside UK academia in the

development of a gazetteer service demonstrator. Build a demonstrator focussing on near-contemporary

data which should illustrate the following: The use of a gazetteer to enhance the geographic

searching of one or more existing JISC services The use of a gazetteer to assist in the semi-automatic

geographic indexing of descriptions of JISC resources Reference use through the provision of a command

driven web-based interface, to show the types of queries that could be answered by a well-populated service

Objectives (2) Investigate:

The issues involved in making the gazetteer a Z39.50 target SOAP (web services) as an access mechanism The utility and usability of the ADL Gazetteer Content Standard Questions about performance and scalability of the service The level of interest and commitment of interested parties

outside tertiary education The costs involved in populating the gazetteer, linking the data and

quality assuring the data Negotiate with data owners to use the key core datasets required to

populate the gazetteer Suggest ways in which data can be kept up-to date, and what kind of

quality assurance on data input will be required Carry out focus groups to assess the needs of the stakeholders for a

full gazetteer service and promote the possibilities of a fully functioning service

Deliverables

A functioning scalable demonstrator gazetteer service that has the potential to be fully integrated into the JISC Information Environment

A report on who the relevant stakeholders are and how the needs of the user group will be met

(An exit strategy - Phase III)

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Query: Archaeological sites within the city of York?11

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