map/archive/generated-history/WORLD_NATIVE_FINAL_NOTES.md

World-native patch generator final notes

Implemented

• Regeneration and expansion now call the same generateUnifiedWorldNativePatchCandidate() path.
• World-native seed construction excludes candidate origin, candidate size, and selection/context rectangles.
• Padding-invariant geographic coordinates are arrayX - world.originX and arrayY - world.originY.
• Terrain, settlement jitter, land-use/human geography inputs and patch-noise paths use world-coordinate context.
• Expansion is split on a canonical world-coordinate grid; internal tiles share the pre-operation generated-coverage snapshot.
• Large/tiled expansion keeps final terrain/admin/transport coherence as one aggregate pass.

Verified

• Left/top world padding: elevation, sea, plain, agriculture, populationDensity, prefectureRegionId and adminId all match exactly over 16,800 compared cells.
• Regeneration reports unified-world-native-patch; tiled expansion reports unified-world-native-patch-tiled.
• Large Worker expansion completes with seam clean.
• STEP15 and STEP17 pass.
• Existing river/capital/tiny-prefecture/frontier regressions pass.
• Freeform lasso completes with seam clean.

Remaining contextual edge behavior

World-native base generation is invariant, but the outer seam is not frozen forever. When a selection is enlarged, cells that used to be the outer seam become interior and are recomputed by final seam/admin coherence. In the 258x183 -> 259x184 stress comparison, sea and adminId are identical in the common area; prefecture IDs differ in ~5.1% and elevation differs in ~3.9% (mean absolute difference ~0.00518). These differences are predominantly the final outer-boundary coherence layer, not a change of the underlying world-coordinate generator.