§2 — Partial data When geometry inference needs help — and when it doesn't
Inference works backwards from the extent of your data, so it cannot tell a small full wafer apart from a slice of a big one. A — a tested half-wafer with no geometry is mistaken for a small full wafer and mis-centred. B — supplying waferConfig.center (the prober coordinate of the wafer centre) anchors it correctly. Csparse data (here every other row and column) is different: positions are missing but the extent still reaches the wafer edge, so the centre and diameter are inferred correctly without a center hint.
A — partial, inferred (wrong)
Half wafer, no geometry. The right-half data is treated as a small full wafer and re-centred on its own midpoint.
B — partial, anchored (correct)
Same half + waferConfig.center: { x: 0, y: 0 }, diameter 300, die 8×12 mm. center anchors prober (0,0) to the true wafer centre, so the tested half sits on the right side of a full 300 mm wafer.
C — sparse, inferred (correct)
Every other row & column; die 8×12 mm, no center. Positions are missing across the whole wafer, but the extent still reaches the edge — so the centre and diameter resolve correctly without a center hint.