Spatial interpretations of preposition "at"

Abstract

The current keyword- and substring matches-based retrieval methods most search engines rely on to answer spatial queries ignore the more specific interpretations of spatial relations. Moreover, the use of the general preposition "at" in natural language queries results in underspecified locations. This paper examines the use of "at" in a set of crowdsourced place descriptions and develops a methodology for interpreting "at" as one of the more location-specific, closely related spatial prepositions "in", "on", or "by". The application of suggested schemas in the paper enables the interpretation of "at" according to the granularity level and classification type of the spatial feature it refers to. The crowdsourced results show that most people use "at" to locate themselves either in relation to buildings, or to (naturally or artificially) bounded outdoor areas (at street level). When used with building level reference features, "at" is more likely to be interpreted as "in" the feature (mostly indoors) and less so "by" it. For reference features at street level, "at" is more likely to be interpreted as "in" the reference feature's region (within a bounded outdoor area) and less so "on" it (e.g., a water surface). The results indicate it is possible to use the proposed methodology for enabling search engines to better rank the results returned to natural language spatial queries by appropriately interpreting "at". The paper's research outcomes are an example of the use of crowdsourced information for improving the interaction between users and services.