This research paper is a thesaurus construction for the interdisciplinary subject of landscape planning. The personnel doing the indexing of documents at the Swedish University of Agricultural Sciences had earlier expressed a need for such a work within the fields of Landscape Architecture and Landscape Engineering. However our objective was not to create a complete thesaurus, but instead a basic construction which the personnel at the Agricultural University could expand upon. The actual construction is based upon ISO 2788-1986, Documentation Ð Guidelines for the establishment and development of monolingual thesauri, and Aitchison, Gilchrist and BawdenÕs Thesaurus Construction (1997). The line of enquiry taken has dealt with the problems relating to the collection, selection and control of indexing terms.

The aim of this thesis is to examine how thesauri constructed with latent semantic indexing LSI are performing when used for query expansion. There is a well-known problem with synonymy in information retrieval and one solution to this problem is to use a thesaurus. In this thesis thesauri are created automatically to find statistically related words and not only synonyms. LSI is a method that uses singular value decomposition SVD to reduce dimensions in a matrix and find latent relationships between words. We constructed nine thesauri and used them for query expansion in a Swedish database, GP_HDINF.