Proximity Zones

Place test points of interest, compute live Haversine distances, and trigger enter/exit events when the device crosses a radius boundary.

Zone visualiser

Your position is the blue dot. Coloured rings are zone radii. Drop POI here places a test point at the current GPS position.

Haversine formula gives the great-circle distance between two lat/lng points on a sphere, accounting for Earth's curvature. For distances under 10 km the simpler equirectangular approximation is accurate to within 0.1 % and faster to compute: d = R × √((Δlat)² + (cos(lat) × Δlng)²).

Entry / exit log

Zone transitions fire when the device crosses a POI's radius boundary. Hysteresis (a small dead-band) prevents rapid re-triggering at the boundary.

No events yet.