The Bartlett Centre for Advanced Spatial Analysis


CASA Working Paper 25


1 July 2000

Weighted and metric surface networks - new insights and an interactive application for their generalisation in TCL/TK

The idea of characterising the different forms of natural topographic surfaces by a topological model based on their fundamental surface features has attracted many proposals. In this paper, a detailed discussion and new proposals on various issues related to the concept, generation, and visualisation of two graph theoretic based surface topology data structures - Weighted Surface Networks and their improved version, Metric Surface Networks - are presented.

Also presented is an interactive Tcl/Tk application called Surface Topology Toolkit, which has been developed to support the discussion on aspects of their generalisation and visualisation. The highlight of the Surface Topology Toolkit is the utility to allow arbitrary contraction unlike the usual vertex importance based criterion. This paper proposes that effective automated surface topology modelling based on these surface networks requires (a) further research in the development of 'computing' algorithms that will accurately locate critical surface points, be able to establish topological links, and also check topological consistency, (b) transforming their 2D straight line graph like appearance to 3D to improve visualisation and contraction, and (c) assessment and userawareness about the effects of each type of contraction criterion on the topography.

This working paper is available as a PDF. The file size is 576KB.

Authors: Sanjay Rana, Jo Wood

Publication Date: 1/7/2000

Download working paper No. 25.