GeoS 2009 was the third edition of the International Conference on Geospatial Semantics. It was held in Mexico City, December 3-4, 2009. Within the last years, geospatial semantics has become a prominent research ?eld in GIScience and related disciplines. It aims at exploring strategies, c- putational methods, and tools to support semantic interoperability, geographic information retrieval, and usability. Research on geospatial semantics is a m- tidisciplinary and heterogeneous ?eld, which combines approaches from the g- sciences with philosophy, linguistics, cognitive science, mathematics, and c- puterscience.WiththeincreasingpopularityoftheSemanticWebandespecially the advent of linked data, the need for semantic enablement of geospatial s- vices becomes even more pressing. In general, semantic interoperability plays a role if data are acquired in a di?erent context than they are ?nally used for. This is the case when shifting from the document Web to the data Web. The core idea of linked data is to make information contributed by various actors, with di?erent cultural backgrounds, and di?erent applications in mind available to the public. Understanding, matching, and translating between the concep- alizations underlying these data becomes a key challenge for future research on geospatial semantics. Thisvolumecontainsfullresearchpapers,whichwereselectedfromamong19 submissions received in response to the Call for Papers.Eachsubmission was - viewedbythreeorfourProgramCommitteemembersand10paperswerechosen for presentation. The papers focus on foundations of geo-semantics, the formal representationof geospatialdata, semantics-basedinformationretrieval and r- ommender systems,spatialqueryprocessing,aswellasgeo-ontologiesandapp- cations.Overall,adiversebodyofresearchwaspresentedcomingfrominstitutions in Austria, Germany,Mexico, The Netherlands, Spain, Taiwan, and the USA.
