Research note

Reading plan: terrain material boundaries

Reading plan for terrain material boundaries (boulders, gravel, splash/swash, beach):

  1. Geomorphology (why zones exist): Hjulström–Sundborg curve — flow energy vs grain size gives erosion/transport/deposition thresholds; material boundaries = energy gradients, implementable from flux/slope fields. Masselink, Hughes & Knight, Introduction to Coastal Processes and Geomorphology (2nd ed., ISBN 978-1-4441-2240-4) for swash zone, beach profiles, sediment sorting. Wentworth grain-size scale + angle of repose for talus/boulder fields.

  2. Ontology (kind of boundary): Smith #KSESR8 fiat vs bona fide; #WYP3G6 esp. #W5DSFW on continuous (lake→marsh→wetland) vs gapped concept transitions — gradient vs crisp boundaries should be represented differently; #7YZU95 mereotopology; #XZX6PE vague reference.

  3. Graphics: Peytavie, Galin, Grosjean, Mérillou, “Arches: A Framework for Modeling Complex Terrains”, CGF 28(2) 2009, doi:10.1111/j.1467-8659.2009.01385.x — layered material stacks (bedrock/rocks/sand/water) with angle-of-repose stabilization; NOT yet in corpus, candidate import. Desertscape Simulation (Paris et al. ~2019) for aeolian sand. In corpus: #AK7NGE riverscapes, #C4AY2M foam/spray, #8SERGP breaking waves, #5KNTTV transition-between-representations pattern.

Unifying idea: a terrain boundary is where a process changes regime (transport threshold, repose angle, wetting frequency). Connects to moppe’s waterline-as-zero-set (RFC-007) — the wet/dry contour is a regime boundary.