FA-70794 / GIS polygon topology / Member archive

Dissolve grouping by attribute and shared edges: exact key comparison · case 04

Numeric 1 and text "1" zones are merged.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Input [polygons, keys]: closed rings on a noded coverage and one attribute value per polygon. Polygons are merged when their keys are exactly equal (type-sensitive, None never merges) and they share at least one edge, transitively. Return the groups as ascending index lists, the list of groups sorted by first index.

Why this case matters

Dissolving parcels into zoning or ownership blocks is a core GIS operation; grouping errors merge blocks that only touch at a corner or split contiguous ones.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression #4	`[[0, 1, 2], [3, 4, 5], [6, 7, 8]]`	`[[0], [1], [2], [3, 4], [5], [6, 7, 8]]`	Failed

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