Journal of Geographical Systems

, Volume 13, Issue 4, pp 327–354

Analytical methods for error propagation in planar space–time prisms

  • Tetsuo Kobayashi
  • Harvey J. Miller
  • Walied Othman
Original Article

Abstract

The space–time prism demarcates all locations in space–time that a mobile object or person can occupy during an episode of potential or unobserved movement. The prism is central to time geography as a measure of potential mobility and to mobile object databases as a measure of location possibilities given sampling error. This paper develops an analytical approach to assessing error propagation in space–time prisms and prism–prism intersections. We analyze the geometry of the prisms to derive a core set of geometric problems involving the intersection of circles and ellipses. Analytical error propagation techniques such as the Taylor linearization method based on the first-order partial derivatives are not available since explicit functions describing the intersections and their derivatives are unwieldy. However, since we have implicit functions describing prism geometry, we modify this approach using an implicit function theorem that provides the required first-order partials without the explicit expressions. We describe the general method as well as details for the two spatial dimensions case and provide example calculations.

Keywords

Spatial error Error propagation analysis Geographic information science Time geography Space–time prisms 

JEL Classification

C1 R4 

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Tetsuo Kobayashi
    • 1
  • Harvey J. Miller
    • 1
  • Walied Othman
    • 2
  1. 1.Department of GeographyUniversity of UtahSalt Lake CityUSA
  2. 2.Theoretical Computer Science Group, Department WNIHasselt UniversityDiepenbeekBelgium

Personalised recommendations