Workshop on Geographic Information Retrieval, SIGIR 2004
Ross Purves
Department of Geography
University of Zürich
Switzerland

Chris Jones
School of Computer Science
Cardiff University
Wales, UK

rsp@geo.unizh.chc.b.jones@cs.cardiff.ac.uk

Geographic Information Retrieval is fast emerging as an interdisciplinary hot-topic,
both in an academic and commercial sense. Retrieving data based not only on
conceptual key words, but some notion of the locational relevance of the information
requires research of a range of techniques, for example• the extraction of geographic terms from structured and, morechallengingly, unstructured data;• the identification and removal of ambiguities in such extraction
procedures;• methodologies for efficiently storing information about locations andtheir relationships;• development of search engines and algorithms to take advantage ofsuch geographic information;• the combination of geographic and contextual relevance to give ameaningful combined relevance to documents; and• techniques to allow the user to interact with and explore the results ofqueries to a geographically-aware IR system.
The idea for this workshop germinated, as a result of the organisers’ involvement in aproject focussing on Geographic Information Retrieval (Spatially Aware Information
Retrieval on the Internet or SPIRIT). Our project involves researchers frominformation retrieval, computation geometry, geographic information science,national mapping agencies, computing science and cartography. Such a diverse groupreflects the interdisciplinary nature of research in this field, and we decided thatorganising a workshop within the auspices of SIGIR 2004 would be an ideal
opportunity to bring together the growing community of researchers and practitioners
working in the field of geographic information retrieval (GIR) to both discuss
progress within the field and identify future research strands.
The workshop was divided into four sessions, entitled GIR Systems, Problems in GIR,
Extracting Geographic Information from Unstructured Text and Test Collections
respectively. The intention was to provide an opportunity to describe some
applications of Geographic Information Retrieval before working through a set of
specific research themes and finally closing the workshop with a discussion of thepossibilities for joint outcomes from the workshop.
The session on GIR systems opened with a talk from Sanderson and Kohler entitledAnalysing geographic queries. They presented the results of analysis of a log ofqueries submitted to the Excite search engine with a view to understanding thefrequency and nature of geographically-specific queries. They found that about one
fifth of all queries submitted were geographical as determined by the presence of ageographical term such as a place name, a post code, a type of place or a directional
qualifier such as north.
The second paper in the session - Yellow page driven methods of collecting andscoring spatial web documents - described a complete GIR system implemented by
Sagara and Kitsuregawa. This paper explained aspects of the system for retrieving andscoring geographically specific documents from the web with a prototype spatial
search engine. They used yellow pages to generate key words to find documents on
the web relating to listed businesses. These were then scored, according to measuresof popularity and reliability, and spatially indexed within the web search engine.
Gey and Carl, in a paper entitled Geotemporal access to multilingual documents
addressed the issue of indexing Russian news articles with respect to space and time,
for use in a map-based query and retrieval system. A major issue was thetransliteration of Romanized gazetteer versions of place names with the Cyrillic
names used in the original texts – merging such schemes across spatial datasets is amajor challenge in multilingual GIR.
Given a set of coordinates how can they be transformed to appropriate textual names?
Naaman et al. used digital map data to determine the containing regions of thecoordinates of digital photographs and hence assign names based on importancecriteria in a paper called Assigning textual names to sets of geographic coordinates.
They also linked the resulting place name directionally to major nearby cities toprovide context (e.g. 40kms NE of San Francisco). An important part of this work
was an initial evaluation of the system’s success in assigning place names, whichshowed that the algorithms implemented were generally successful.
The final paper in this session, Information mining: extracting, exploring andvisualising geo-referenced information, from Chrisment et al. described the use oftechniques based on data mining and exploration to aid users in analysing andvisualising geo-referenced data. They gave an example of a case study where data
based around the country of the authors’ affiliation was used to explore publication
data from their institution. Such techniques, which exploit large multi-dimensional
datasets are likely to increase in importance in GIR.
The second session was titled Problems in GIR and opened with a paper from
Arampatzis et al. entitled Web-based delineation of imprecise regions. This paper firstused the web to identify places which were related with a region whose borders were
spatially ill-defined, for example the south of France. Locations associated with suchan imprecise region were geo-referenced, and a point dataset of candidate locations
constructed. This set of candidate locations was then used to delineate a polygon
based boundary for the imprecise region.
The second paper in this session, Ranking and representation for GIR, from Larson
and Frontiera explored the sensitivity of GIR to different spatial representations. A
range of representations can be used for spatial domain in metadata, from a fullpolygon to a centroid or minimum bounding rectangle. This paper examined thesensitivity of matching and ranking approaches to different representations andexplored the use of a probabilistic ranking method. Finally, the addition of geographic

context in the form of a shorefactor, describing the percentage of a query region on oroffshore, was explored.
The final paper in this session, Spatial search, ranking and interoperability, from
Janée and Frew was the first of two papers describing the extensive experiences of theAlexandria Digital Library (ADL) project in GIR. The paper set out the challenges inproviding a set of interoperable interfaces sufficiently detailed to allow useful spatial
querying and yet sufficiently lightweight to be taken up by many organisations. Key
concepts in such work are the nature of spatial representations and the spatialpredicates (e.g. overlaps, inside, etc.) which are considered a minimal set required formeaningful spatial queries to be performed. Important issues in this paper included
the need for geodetic continuity in representation across the globe and the suggestionthat the basic set of spatial predicates used be limited to the relation intersects.
The third session, Extracting Geographic Information from Unstructured Text,
opened with a paper from Silva et al. titled Adding geographic scope to web resources
investigated the problem of determining the geographical scope of web documents, inorder to index them in the tumba! web search engine. After transforming web
documents to a structured XML/RDF format they were progressively augmented withgeographical descriptors through a sequence of lexical analysis, geographical entity
recognition and semantic and web inference procedures.
The specific aspect of geographical scope determination concerned with recognising
the presence of place names in documents was the subject of the paper by Nissim etal., Recognising geographical entities in Scottish historical documents. They showedthat an existing machine learning tool, specifically a maximum entropy tagger, can beused quite effectively to detect the presence of place names using a manually
generated training data set. They worked with a challengingly “noisy” data source, theStatistical Accounts of Scotland.
Amitay et al. presented a paper on Finding the geographical focus of web-pages
which used the results of a geographic name tagging procedure to try to determine themain geographic focus of a web document when several place names are mentioned.
If there are several places mentioned along with their parent region, then theimmediate parent is assumed to be a focus of the document. The procedure depends
upon the use of a hierarchically-structured gazetteer.
The final paper in this session, Extracting spatial information: grounding, classifying
and linking spatial expressions looked at the uncertainty introduced into theclassification of documents according to the occurrence of place names due to thevarious uses of place descriptors in text. Schilder et al. used a part-of-speech tagger toidentify spatial expressions which were then disambiguated with a search procedure
to distinguish between place names used to identify a location and places referring,for example, to governments, to the nationalities of people and to the destinations ofgoods.
The final session of the workshop, Test collections provided an opportunity for theparticipants to discuss possibilities for the development of test collections to be used
across the GIR community in a similar way to the successful TREC collections. The
first paper in this session, from Hill et al., Research directions in georeferenced IRbased on the Alexandria Digital Library Project, provided a further insight into thework of the ADL, and in particular experiences related to georeferencing through theuse of gazetteers. The paper proposed the development of a spatial test collection –that is a set of detailed data with which results from the sort of experiments describedby Larson and Frontiera could be compared. Such a reference set would provide a
consistent reference dataset for measuring spatial relevance in terms of different
predicates and representations.
The second paper in this section, Towards a reference corpus for automatic toponym
resolution evaluation by Leidner, presented a detailed proposal for a reference corpus
of text annotated with spatial locations. A detailed discussion of the issues indeveloping such a corpus was presented, including a review of issues such as theselection of an appropriate corpus, selection of a gazetteer and a proposed mark-up
scheme.
This paper was complimented by the final paper of the workshop, from Clough andSanderson entitled A proposal for comparative evaluation of automatic annotation for
geo-referenced documents. This paper presented a further proposal for thedevelopment of test datasets containing annotated geographic entities. The session
closed with a discussion on possibilities for future collaborations on test collections.
A very positive result of these discussions was a contribution to CLEF (Crosslanguage evaluation forum: clef.iei.pi.cnr.it:2002/) discussing the possibilities forestablishing a GIR track as part of CLEF.
The workshop closed with a discussion as to its worth and future affiliation. All of
those present were happy that the workshop had proved fruitful, and interested inattending future workshops. It was agreed that SIGIR had provided an ideal venue tobring together researchers in GIR, but this should not preclude holding the workshop
with other conferences, in line with its interdisciplinary status.
The workshop proceedings are available online at http://www.geo.unizh.ch/~rsp/gir/.
A special issue of Computers, Environment and Urban Systems is also planned.