The area through which people or vehicles must pass to be counted.
When using video to count people, you position a cctv camera above the counting area or zone. The system detects and counts people as they cross through the zone. Typically a zone will cover a doorway but it might instead be across a corridor, outside a shop window, above a turnstile or over a store display unit.
For vehicles the zone might cover a small strech of road or a junction.