Line Breach Rule

Owned by Marvin Chen (Unlicensed)
Last updated: Dec 14, 2017
3 min read

A line breach rule will raise an alarm when tracked objects crosses a line and is the recommended mechanism for securing airport CP lines or intruder detection.

This guide helps you understand line breach rules, when to use them and how best to set them up.



On this page:

Creating a Breach Line

Each line breach rule is based on one Breach Line. The rule is triggered when a track crosses the breach line.



Consider for example this prison:

  • Case:

    • notify tracks that leaves the area by the perimeter fence

    • Ignore tracks departing from the parking space.

  • We create a New Breach Line from the side panel. 

Controls:

  •  

    • Vertex - click and drag to move

    • Vertex - Right click to remove

    • Centre Box - Right click to add new vertex

    • Breach Direction - Right click to toggle on/off

    • Line segment name can be set in the side panel list

The solid orange arrow indicates the directions we are allowed to cross this line.

The arrows on each side of the line can be toggled independently by right clicking on the arrow.

Thus we can configure each section of the breach line to allow one way traffic, traffic for both directions, or disallow crossing entirely.

Currently, this line will allow us to cross from north to south, but not south to north.





For this particular application, we have renamed our breach line to "Prison Perimeter", disallowed cross from inside to outside and set a colour for the breach line as blue.

Final result on screen after saving the changes:

Create a Line Breach Rule

A breach line by itself does not do anything. We will need to create a new Line Breach rule and alarm configuration to use this breach line.

Alarm Description: You can use smart strings {LINE} {LINESECTION} for the line or line section names.

Breach Line: The breach line to use when calculating this rule

Alarm Reset Timeout: Duration the track remains in alarm after line is breached in seconds. Recommended is 5 seconds.

Minimum Seen Count: To avoid false alarms, only consider tracks after they have been sighted this many times. Recommended is 5.

Advanced Configuration

Line breach rule works with Allowance (can be set in Advanced configuration) in a slightly different way compared to other rules. Allowance is reset for the line breach rule when the track returns back to the original side of the line or moves in a way that its location compared to the original location before it crossed the line is no longer crossing the line. For most purposes, our recommendation is to have a moderately low allowance and instead use the recommended minimum seen count to reduce false alarms.



Related information