Geocoding Is Quietly Costing You: Exposure at the Address, Not the Postcode
Ask a property insurer where a given risk is located and you'll usually get a postcode. Ask where it actually is — the specific building, its elevation, its distance from the coast or the river — and you'll often get a shrug. Most insurers geocode exposure to the postcode centroid: a single point that represents an area which might span kilometres. For everyday admin, fine. For catastrophe modelling, flood rating, and accumulation management, it's a quiet, systematic error that costs real money. The centroid problem A postcode centroid places every risk in that postcode at the same point — the geographic middle. But hazards don't respect postcode boundaries, and they're often sharply local. Flood risk can change completely across a single street depending on which side of a contour you're on. Wildfire risk depends on the specific slope and vegetation. Storm surge depends on metres of elevation. Snap all those risks to one centroid and you've thrown aw...