The axis-specified search is a method of text search, especially for encyclopedia search. Users (searchers) specify an axis of search in addition to keywords. The search results are arranged along the axis. For example, if the axis is "year", the result is a chronological table. The axis can also be "geography" or various types of "quantity".
The most important paper on this research is "Axis-specified Search: A Fine-grained Full-text Search Method for Gathering and Structuring Excerpts". The method of extracting geographical names is described in "A Method of Geographical Name Extraction from Japanese Text for Thematic Geographical Search". Other papers are available here.