Progressive TINs: algorithms and applications

Transmission of geographic data over the Internet, rendering at different resolutions/levels of detail, or processing at unnecessarily fine detail pose interesting challenges and opportunities. In this paper we explore the applicability to GIS of the notion of progressive meshes, introduced by Hoppe [13] to the field of computer graphics. In particular, we describe progressive TINs as an alternate method to hierarchical TINs, design algorithms for solving GIS tasks such as selective refinement, point location, visibility or line of sight queries, isoline/contour line extraction and provide empirical results which show that our algorithms are of considerable practical relevance. Moreover, the selective refinement data structure and refinement algorithm solves a question posed by Hoppe.