ABSTRACT
The digital terrain modelling capabilities of GIS are very limited and inflexible for the increasing application demands of today's users. Whilst terrain data are becoming more readily available at finer resolutions, DTM data structures have remained static and intransigent to this change. Many users require a wider variety of data structures and algorithms, which are suited to the specific requirements of their particular applications. This chapter identifies alternative data structures which meet these requirements and provides a comparison on the basis of adaptability to the terrain characteristics and constrained multiscale modelling. These are the primary considerations for users who need to maintain national or large-area terrain databases, where storage efficiency is essential.
