@inproceedings{9090537730a548e5b1901224b825a4fe,
title = "Reasoning about cardinal directions using grids as qualitative geographic coordinates",
abstract = "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.",
author = "Lars Kulik and Alexander Klippel",
note = "Publisher Copyright: {\textcopyright} Springer-Verlag Berlin Heidelberg 1999.; International Conference on Spatial Information Theory, COSIT 1999 ; Conference date: 25-08-1999 Through 29-08-1999",
year = "1999",
doi = "10.1007/3-540-48384-5_14",
language = "English (US)",
isbn = "3540663657",
series = "Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)",
publisher = "Springer Verlag",
pages = "205--220",
editor = "Mark, {David M.} and Christian Freksa",
booktitle = "Spatial Information Theory",
address = "Germany",
}