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Spatial Extent Models for Natural Language Phrases Involving Directional Containment
Author(s) -
Singh Gaurav,
By Rolf A.
Publication year - 2015
Publication title -
transactions in gis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 63
eISSN - 1467-9671
pISSN - 1361-1682
DOI - 10.1111/tgis.12105
Subject(s) - phrase , consistency (knowledge bases) , representation (politics) , variety (cybernetics) , computer science , geography , natural language processing , artificial intelligence , politics , political science , law
We study the problem of assigning a spatial extent to a text phrase such as ‘central northern C alifornia’, with the objective of allowing spatial interpretations of natural language, and consistency testing of complex utterances that involve multiple phrases from which spatial extent can be derived. The work presented addresses alternative spatial extent assignations, and the evaluation of those alternatives to decide on the best performing ones. Three important classes of these phrases are identified and we call them full direction phrases , half‐direction phrases , and extreme direction phrases , respectively. Examples of these are: ‘north‐western C alifornia’, ‘central northern C alifornia’, and ‘extreme south‐eastern C alifornia’. Such descriptions vaguely delineate a spatial extent, and we attempt to derive a region‐representation for them. Our approach is to identify a number of extent assignation parameters, which are used to derive a variety of spatial extent models, each of which we evaluate against a large gazetteer corpus. Three example assignation parameters used are: choice of center, choice of shape of central sector, and choice of shape of outer sectors. The corpus used for the evaluation is the two‐volume O rnithological G azetteer of B razil ( P aynter and T raylor 1991a, b). It allows us to compare the spatial extent assignations and derive recommendations for such assignations for future use.