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UID:pretalx-foss4g-europe-2026-HFJQ9H@talks.osgeo.org
DTSTART;TZID=EET:20260701T150000
DTEND;TZID=EET:20260701T153000
DESCRIPTION:Hexagon based grids have gained particular attention in geospat
 ial applications with their use in discrete global gridding systems (DGGS)
 . A feature of many DGGS is the indexing of the grid cells at different re
 solutions to uniquely identify the cells. For hexagon based DGGS like H3 o
 r IGEO7 the underlying system for indexing is based on 2D generalized bala
 nced ternary (GBT).\n\nGBT was originally described in the 80s for use in 
 image analysis because of the similarity between hexagon grids and biologi
 cal vision systems. Here we discuss how GBT encodes indexes and discuss th
 e basics of GBT arithmetic in 2D hexagon grids. We demonstrate how GBT ari
 thmetic can be employed for neighbour traversal and more broadly spatial a
 lgorithms on hexagonal girds. Finally\, we will look at the special cases 
 that arise in the application of GBT to indexing in DGGS\, which are the c
 onsequences of necessary pentagons and non-GBT arranged base zones.
DTSTAMP:20260605T060155Z
LOCATION:A11
SUMMARY:Indexing with Hexagons: GBT Explained - Javier Jimenez Shaw\, Westo
 n Renoud
URL:https://talks.osgeo.org/foss4g-europe-2026/talk/HFJQ9H/
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