Abstract: A text retrieval method called the thematic geographical search method has been developed and applied to a Japanese encyclopedia called the World Encyclopedia. In this method, the user specifies a search theme using free words, then obtains a sorted list of excerpts and references to encyclopedia sentences that contain geographical names. Using this list, the user can open maps that indicate the location of the names. To generate an index of names for this searching, a method of geographical name extraction has been developed. In this method, geographical names are extracted, matched to names in a geographical name database, and identified. Geographical names, however, often have several types of ambiguities. Ambiguities are resolved using context analysis and several other techniques. As a result, the precision of extracted names is more than 96% on average. This method depends on features of the Japanese language, but the strategy and most of the techniques can be applied to texts in English or other languages.
Introduction to this research theme: Axis-Specified Search (Thematic Search)