Zone docs (#8047)

* Update zone docs

* Document zone inertia in zone docs

docs/docs/configuration/index.md

@@ -527,7 +527,7 @@ cameras:
         # Required: List of x,y coordinates to define the polygon of the zone.
         # NOTE: Presence in a zone is evaluated only based on the bottom center of the objects bounding box.
         coordinates: 545,1077,747,939,788,805
-        # Optional: Number of consecutive frames required for object to be considered present in the zone. Allowed values are 1-10 (default: shown below)
+        # Optional: Number of consecutive frames required for object to be considered present in the zone (default: shown below).
         inertia: 3
         # Optional: List of objects that can trigger this zone (default: all tracked objects)
         objects:

docs/docs/configuration/zones.md

@@ -56,3 +56,27 @@ camera:
 ```
 
 Only car objects can trigger the `front_yard_street` zone and only person can trigger the `entire_yard`. You will get events for person objects that enter anywhere in the yard, and events for cars only if they enter the street.
+
+### Zone Inertia
+
+Sometimes an objects bounding box may be slightly incorrect and the bottom center of the bounding box is inside the zone while the object is not actually in the zone. Zone inertia helps guard against this by requiring an object's bounding box to be within the zone for multiple consecutive frames. This value can be configured:
+
+```yaml
+camera:
+  zones:
+    front_yard:
+      inertia: 3
+      objects:
+        - person
+```
+
+There may also be cases where you expect an object to quickly enter and exit a zone, like when a car is pulling into the driveway, and you may want to have the object be considered present in the zone immediately:
+
+```yaml
+camera:
+  zones:
+    driveway_entrance:
+      inertia: 1
+      objects:
+        - car
+```