# Course Geometry > Canonical: https://pinflag.io/technology/course-geometry PinFlag’s maps and lies come from commercial course geometry data, combined with operator-verified courses. Every course passes a defect quarantine before it can back live numbers, and broken geometry disables live strokes gained rather than faking it. *The PinFlag iOS app is in pre-release. Leave your email and we’ll tell you the moment it’s available.* PinFlag’s maps and lies come from commercial course geometry — greens, tees, fairways, bunkers, water, boundaries — combined with operator-verified courses. “Verified” has one standard: a professional survey or a physical ground-truth walk. Every course passes a defect quarantine (units, topology, lie registration, hole count) before live strokes gained is allowed on it; broken geometry disables live SG rather than faking it. Out-of-bounds is never synthesized. ## Why it matters - A wrong map produces confidently wrong lies on every shot — the failure mode you never see. - Verification should mean something specific, not be a marketing adjective. ## How it works 1. **A full surface model** — Greens, tees, fairways, rough, bunkers, water, boundaries, and trees — plus pins, tee points, and play-line corridors. 2. **One verification standard** — A course is verified by a professional survey or by an operator’s physical ground-truth walk — one bar, no tiers. 3. **Quarantine before trust** — Units, topology, lie registration, spread, and hole count are checked per course; failures disable live strokes gained. ## Everything Course Geometry does - Full surface model: greens, tees, fairways, rough, bunkers, water, OB, boundaries, trees - One verification standard: professional survey or operator ground-truth walk - Defect quarantine on every course — units, topology, lies, spread, hole count - Broken geometry disables live SG — it is never masked - Out-of-bounds is never synthesized - Course data cached offline; honest “Course unavailable” when geometry isn’t ready ## Who it’s for Players who have met the wrong-yardage app before, and want to know why this one refuses to guess. ## What’s different - Out-of-bounds is never synthesized — absence is recorded, not papered over. - A quarantined course says “Course unavailable” instead of rendering a fiction. - Course data is cached for offline play; imagery streams and says so. ## Frequently asked questions ### What does “verified course” mean in PinFlag? Verified means the geometry comes from a professional survey or an operator’s physical ground-truth walk — one standard, and broken geometry never verifies regardless of source. ### Where does the course data come from? From commercial course geometry data, combined with operator-verified courses. PinFlag validates every course before live numbers are allowed on it. ### What happens on a course that fails validation? Live strokes gained is disabled with a plain banner, and nothing on that course can present as Measured. The app never swaps in fake geometry.