Reasoning about cardinal directions using grids as qualitative geographic coordinates

Lars Kulik, Alexander Klippel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

17 Scopus citations


In this article we propose a calculus of qualitative geographic coordi- nates which allows reasoning about cardinal directions on grid-based reference systems in maps. Grids in maps can be considered as absolute reference systems. The analysis reveals that the basic information coded in these reference systems is ordering information. Therefore, no metric information is required. We show that it is unnecessary to assume a coordinate system based on numbers in order to extract information like a point P is further north than a point Q. We investigate several grids in maps resulting from different types of projections. In addition, a detailed examination of the north arrow is given since it supplies a grid with ordering information. On this basis, we provide a general account on grids, their formalization and the inferences about cardinal directions drawn using qualitative geographic coordinates.

Original languageEnglish (US)
Title of host publicationSpatial Information Theory
Subtitle of host publicationCognitive and Computational Foundations of Geographic Information Science - International Conference COSIT 1999, Proceedings
EditorsDavid M. Mark, Christian Freksa
PublisherSpringer Verlag
Number of pages16
ISBN (Print)3540663657, 9783540663652
StatePublished - 1999
EventInternational Conference on Spatial Information Theory, COSIT 1999 - Stade, Germany
Duration: Aug 25 1999Aug 29 1999

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


OtherInternational Conference on Spatial Information Theory, COSIT 1999

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science


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