Integration of linear and areal hierarchies for continuous multi-scale representation of road networks

Abstract

Spatial data can be represented at different scales, and this leads to the issue of multi-scale spatial representation. Multi-scale spatial representation has been widely applied to online mapping products (e.g., Google Maps and Yahoo Maps). However, in most current products, multi-scale representation can only be achieved through a series of maps at fixed scales, resulting in a discontinuity (i.e., with jumps) in the transformation between scales and a mismatch between the available scales and users' desired scales. Therefore, it is very desirable to achieve smoothly continuous multi-scale spatial representations. This article describes an integrated approach to build a hierarchical structure of a road network for continuous multi-scale representation purposes, especially continuous selective omission of roads in a network. In this hierarchical structure, the linear and areal hierarchies are constructed, respectively, using two existing approaches for the linear and areal patterns in a road network. Continuous multi-scale representation of a road network can be achieved by searching in these hierarchies. This approach is validated by applying it to two study areas, and the results are evaluated by both quantitative analysis with two measures (i.e., similarity and average connectivity) and visual inspection. Experimental results show that this integrated approach performs better than existing approaches, especially in terms of preservation of connectivity and patterns of a road network. With this approach, efficient and continuous multi-scale selective omission of road networks becomes feasible.

Keywords:

• multi-scale representation
• road network
• areal hierarchy
• linear hierarchy

Acknowledgements

This research is mainly supported by the Research Grants Council of Hong Kong (PolyU 5221/07E) and partially supported by Southwest Jiaotong University. The authors would like to express special thanks to all the anonymous reviewers and the editor for their valuable comments and also to Prof. Chris Gold from the University of Glamorgan for revising the writing. We are also thankful to the Land Department of Hong Kong and the Land Information of New Zealand for providing the experimental data.