David Parker

Analysis of global pattern features

Abstract A fundamental method for analysing the global features of visual patterns is presented. Pattern features are considered to be synonomous with non-random distributions in the pattern statistics. In particular, the statistics of the chords of the patterns are considered, leading to the histograms of the chord lengths and angles. Peaks in these histograms indicate the presence of structure in the pattern. It is demonstrated how the points of the pattern contributing to this structure can be enhanced and/or extracted. It is argued that this is a more fundamental way of obtaining pattern features than other ad hoc methods. The chord space approach allows analytic solutions to be easily obtained for idealized patterns such as circles, parallel lines, etc. A method for implementing the algorithms on a parallel processor is indicated.

A model for spatio-temporal network planning

Temporal GIS research has tended to focus on representing a single history through a series of states. For planning future work involving alternative scenarios a branching model of time may be required, however for large systems such models soon become highly complex. In this paper we introduce the temporal topology model which allows sections of work and the spatial, temporal and logical relationships between them to be represented efficiently together with the associated costs. We then discuss how this model could be used for analysis to determine an optimal plan, illustrated with a case study involving cycle network planning, and briefly describe some practical results which have been obtained.