Generation of Zoomable maps with Rivers and Fjords

TL;DR

The paper tackles the problem of generating zoomable, on-demand terrain with rivers and fjords for games and tabletop use by proposing a recursive subdivision scheme on triangles. Rivers are embedded via edge attributes and propagated through the mesh during subdivision, with explicit rules for long and short edges, multiple surrounding-edge scenarios, and optional variants such as islands in fjords and Penrose tilings to reduce artefacts. Key contributions include a detailed, edge-aware river-placement framework that yields coherent river networks across zoom levels and practical performance figures (≈1.4–1.5 s for large maps on a single core), along with variant options to control artefacts and fjord/island features. The work enables practical, scalable, zoomable maps suitable for gaming and visualization, and suggests clear directions for extending to tetrahedral subdivision and spherical terrains in future research.

Abstract

This paper presents a method for generating maps with rivers and fjords. The method is based on recursive subdivision of triangles and allows unlimited zoom on details without requiring generation of a full map at high resolution.

Figures (13)

• Figure 1: Map showing rivers and fjords at zoom 1, 5, 25 and 125
• Figure 2: Triangle Subdivision
• Figure 3: Map generated by triangle subdivision
• Figure 4: When there is a river on the long edge
• Figure 5: When there is no river on any outer edge