Location programs: triggers

A trigger is a point on the map that fires a piece of content when the display passes it. A commentary clip as you approach the lighthouse, a photo of the bridge as you go under it. The trigger interrupts whatever the zone layer is playing, runs once, and hands back.

Triggers fire from position alone. Nobody presses anything.

Create a trigger

Open your location program and go to the Triggers tab. Place a point on the map and set its options.

A trigger is a point with a radius. Crossing into it fires its content.

Radius (meters)

Radius sets how close the display has to get. The default is 50 m.

Match it to how fast the vehicle travels and how often the position updates. A bus at 50 km/h covers 50 m in under four seconds, so a tight radius on a fast route can be missed between fixes. Widen the radius, or shorten the polling interval on the display's location source.

Content

Content is a Playlist or a Media item. Audio is very common here, playing commentary over whatever the screen is already showing.

Display time (seconds)

Display time defaults to 30. This only applies to still images — a video or playlist plays for its full duration regardless of this setting.

Cooldown

Cooldown sets how long before the trigger can fire again. The default is 120 seconds.

The cooldown is measured from the moment the display is continuously outside the fence. A vehicle that moors on a boundary, or crawls through traffic at the edge of a trigger, cannot re-fire it by drifting in and out. A vehicle lapping a circular route still fires the trigger again on every lap.

Altitude band

Altitude band optionally sets a minimum and maximum altitude, and the trigger only fires within the band.

Use it where a route passes over or under itself, like a road bridge above a canal or a viaduct over a valley floor. A trigger meant for one won't fire on the other.

Fence bearing (degrees)

Fence bearing is optional, takes 0–360, and makes the trigger directional.

Set a bearing and the map draws chevrons showing which way the crossing has to happen. Two triggers at the same spot with opposite bearings give the outbound and inbound legs of a route different commentary. Leave it blank and the trigger fires on any crossing.

A fence bearing makes a trigger one-way. The chevrons show the direction of travel that fires it.

Choose what happens when a trigger interrupts

A program-wide setting, When a trigger interrupts, decides what happens if a trigger fires while something is already playing.

It's set once for the whole program, not per trigger.

• Skip suits a route where triggers are dense and you'd rather not stack commentary on commentary.
• Replace suits sparse, important triggers where missing one matters.
• Queue suits audio commentary on a slow route, where every clip should be heard and a short delay is fine.

Note: Manual cues always replace what's playing, regardless of this setting. If a guide presses a button and nothing happens, it looks like a fault — so cues always take the screen.

Plan a route

A few things make triggers behave well in the field.

Place triggers slightly before the landmark. Commentary that starts as the thing comes into view works better than commentary that starts as it disappears behind you.

Match radius to speed and polling interval. A display polling every 5 seconds on a vehicle doing 60 km/h moves 83 m between fixes. A 50 m radius can be skipped entirely. Widen the radius or shorten the interval. See Set a display's location source.

Use bearings on out-and-back routes, or every trigger fires twice.

Use the cooldown for loops. On a circular route, set the cooldown shorter than a lap so each pass fires. On a route with a long layover next to a trigger, set it long enough to cover the stop.

Good to know

• A trigger fires once per pass. It won't fire again until the display has been outside its fence for the cooldown period, and nothing needs resetting.
• After a trigger finishes, the ambient zone layer is worked out fresh, not restored. The vehicle has moved while the clip played, possibly into a new zone.
• The trigger list order doesn't matter. It's for your reference only — use it to keep yourself organized along the route.

Next steps

• Location programs: manual cues and controller mode
• Set a display's location source
• Location programs: zones and live maps