docs: wayfinder packet for MULTISURFACE type honesty

[grootstebozewolf]

Wayfinder letter for SQL/MM MULTISURFACE (ISO/IEC 13249-3 §4.2.27, WKB 12).

This is a map / tickets / decision packet. It does not implement silent-MULTIPOLYGON elimination, does not mint a second MultiSurface type, and does not merge into JTS #7.

Merge comment (one sentence). MULTISURFACE is a SQL/MM collection of ST_Surface members; the Coq structural pin is CurveGeometry.v : valid_curve_geometry (list CurvePolygon), and the one leftover this card owns is silent emit of MULTIPOLYGON at overlay / hull / TestBuilder — named to_geometry / toLinear stays named, I/O type identity is not op honesty, and Jordan stays on tracker 509.

Destination

Name the silent MultiPolygon-collapse leftover so the next session cannot steal CURVEPOLYGON ticket 32, steal MULTICURVE ticket 34, steal tracker 509, or treat the structural collection pin as overlay honesty.

Living file: docs/scout/map-multisurface.md

Tickets

• Ticket 35 closed as the chart.
• Ticket 36 names the leftover. HOLD implement stands (no Architect SIGN on this leftover). Do not /implement from this letter.

Siblings: COMPOUNDCURVE 29 / 30 on PR #656, CURVEPOLYGON 31 / 32 on PR #657, MULTICURVE 33 / 34 on PR #658. Numbered 35 / 36 so merge does not collide.

Honesty

Three words that say "collapse":

1. Silent MultiPolygon collapse — the leftover (ticket 36).
2. Named Linearize / toLinear / to_geometry — allowed (CurveGeometry.v : to_geometry; JTS MultiSurface.toLinear returns MultiPolygon and is named).
3. Collection / member list — already the structural pin (CurveGeometry.v : valid_curve_geometry). Not Jordan. Not overlay honesty.

HELP names CS / CC / CP and does not name MULTISURFACE. GML3 MultiSurface in NTS core returns MultiPolygon — not SQL/MM type 12. WKB-8-12 is I/O identity. A JTS README note that written MULTISURFACE(CURVEPOLYGON(…)) can re-read as MultiSurface[Polygon] is I/O member-tag degrade, not this leftover.

Cite ISO/IEC 13249-3 only. Do not cite ISO 19125-2.

Parks

• Off JTS Slice A Piece 5b: Route 2 collapse analysis + Route 1 redesign (red phase only) #7. No type-12 reader PR. No GEO-TIN 15–17.
• HOLD a second MultiSurface type. JTS feat: hobby_lemma_4_3 — shared-endpoint closed, no-proper deferred #27 out. JTS feat: valid_geometry_extract Qed — Phase 3 M5 S10 #38 off Slice A Piece 5b: Route 2 collapse analysis + Route 1 redesign (red phase only) #7. No public noder.
• Do not flip F-CP / F-MC / F-MS TRIAGE rows.
• Do not steal tickets 30 / 32 / 34. Do not remint tracker 509. Do not steal 615-h.
• claimId: none · witness: none
• No WSJF / priority from this letter.

topics: arc, wkt
claimId: none
witness: none

  

[cursor]

Superseded by the combined SQL/MM type-honesty packet: #660. Closing this letter so TRIAGE / the prose gate / the ticket index stop colliding.