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topo-detect

Inputs

  • topo-detect MUST read the input and reproject it to EPSG:4326 without correcting any topology defects first, so the issues stage sees the original, unmodified geometry.

Detecting gaps, overlaps and micro-polygons

  • topo-detect MUST report every fully-enclosed hole in the combined shape of all input polygons as a gap, regardless of its size. An open, non-enclosed inlet between two polygons MUST NOT be reported as a gap.
  • topo-detect MUST report every case where two polygons' interiors genuinely overlap, or one fully contains the other, as an overlap, regardless of its size, whenever the input has any coverage violation at all. If the input has no coverage violations, topo-detect MUST report zero overlaps without running the overlap check. Two polygons that only share a boundary edge MUST NOT be reported as an overlap.
  • topo-detect MUST report every micro-polygon part as a micro-polygon, identifying the unit it belongs to.
  • If detecting one kind of defect fails, topo-detect MUST still report the other kinds rather than failing entirely.
  • The issues report MUST list, for every defect: a unique key, its kind (gap, overlap or micro-polygon), its area, its width, and its geometry. A gap entry MUST also carry a compactness score (how thin and elongated its shape is, as opposed to round and plausible); an overlap entry MUST also identify the two units involved. Neither MUST appear on the other kinds' entries.

Outputs

  • topo-detect performs no topology hard gate at all; it is a read-only inspection, not a fix.
  • topo-detect MUST always produce an issues report, even when the input had zero defects.

Configuration (api.topo_detect.detect() / CLI)

  • topo-detect MUST process exactly one input file per call.
  • The issues-report path MUST default to the input path with an _issues suffix.
  • topo-detect MUST raise FileExistsError if the output path already exists and overwriting wasn't requested.
  • step, if given, MUST be one of inputs, issues, outputs; any other value MUST raise ValueError.

Examples

Example 1: basic run, output name chosen automatically

topo-tools topo-detect example.geojson

Example 2: explicit output

topo-tools topo-detect example.gpkg example_issues.gpkg