Ship & Traffic Overlays
Show your own vessel, surrounding AIS traffic and collision-avoidance tools (CPA/TCPA, dead reckoning, camera detection) on the chart.
Where to find it
Map › floating Overlays button (layers icon, top-left of the chart) › My vessel tab (ship icon).
The Overlays button shows a badge with the number of active overlays. Once opened, the panel shows a row of category tabs: pick the tab with the ship icon to reach the overlays described here.
Hierarchy
Overlays (floating panel)
└── My vessel (tab)
├── Own Ship ............ (+ Center map on vessel button)
│ (+ Simulations button)
├── AIS
├── CPA/TCPA
├── Dead Reckoning
├── Detection
└── Camera PiP
Each row is a toggle: one click turns the overlay on (the row gets highlighted), another click turns it off. When an overlay is active and has a prerequisite, an amber info note appears just below it.
Own Ship
Own Ship
What it's for: shows your boat's position on the chart, with its heading and course-over-ground (COG) vector. It's the central reference for all real-time navigation.
How to use it: 1. Open the Overlays panel and switch to the My vessel tab. 2. Click the Own Ship row to enable it. 3. Your position appears on the chart as soon as a position source is available (Signal K or GPS). 4. Two extra buttons appear to the right of the row once the overlay is active (see below).
Options & settings:
| Control | What it does |
|---|---|
| Own Ship toggle | Shows / hides the vessel position, heading and COG vector. |
| Center map on vessel button (crosshair icon) | Only appears while Own Ship is active. Continuously re-centers the map on the boat; ideal for keeping the vessel on screen underway. Click again to stop following. |
| Simulations button (play icon) | Opens the simulations panel to test features without actually navigating (simulated underway navigation, CPA/TCPA collision, dead reckoning, ship detection, MOB, etc.). |
Tips & limits: - Position comes from Signal K or a GPS. Without a connected position source, the boat is not drawn. - The Simulations button is great for exploring features at the dock: it injects fake data (e.g. a vessel beating to windward in the Mediterranean, or a passage through the Strait of Gibraltar) with no real instruments.
AIS
AIS
What it's for: shows surrounding vessel traffic (cargo ships, sailboats, fishing boats…) received over AIS, in real time.
How to use it: 1. Enable the AIS row in the My vessel tab. 2. AIS targets appear on the chart and update as new positions arrive.
Options & settings:
| Control | What it does |
|---|---|
| AIS toggle | Shows / hides AIS traffic targets. |
Tips & limits: - Data source: real-time feed via aisstream.io, or a polling API, depending on configuration. - AIS is the prerequisite for the CPA/TCPA overlay: without AIS targets, no collision computation is possible.
CPA/TCPA
CPA/TCPA
What it's for: computes, for each AIS target, the Closest Point of Approach (CPA) and the Time to CPA (TCPA). This is the collision-avoidance watch tool.
How to use it: 1. First enable the AIS overlay (targets required). 2. Make sure your position is known via Signal K. 3. Enable the CPA/TCPA row. 4. Targets with a dangerous approach are highlighted (red below 0.5 NM).
Options & settings:
| Control | What it does |
|---|---|
| CPA/TCPA toggle | Enables CPA/TCPA computation and display for AIS targets. Color code: red below 0.5 NM. |
Tips & limits: - Prerequisite (amber note shown on enable): AIS overlay active + Signal K (your own ship position). Without your own position, the relative approach cannot be computed. - Keep a visual lookout: CPA/TCPA only covers vessels equipped with and transmitting AIS.
Dead Reckoning
Dead Reckoning
What it's for: computes an estimated position if GPS is lost, based on the last known heading (HDG) and speed-over-ground (SOG), corrected for current. A safety net in case of electronics failure.
How to use it: 1. Check that your position comes from Signal K. 2. Enable the Dead Reckoning row. 3. The estimated position and its drift vector are shown; if GPS is lost, it takes over visually.
Options & settings:
| Control | What it does |
|---|---|
| Dead Reckoning toggle | Shows the estimated position (last HDG/SOG + current) and drift vectors. |
Tips & limits: - Prerequisite (amber note): Signal K (own ship position). - Dead reckoning is more accurate when the last heading and speed were steady; in repeated tacks or rough seas, treat it as an approximation.
Detection
Detection
What it's for: automatic vessel detection by AI (YOLO) from a camera feed, fused with AIS. Helps spot boats not equipped with AIS.
How to use it: 1. Enable the Detection row. 2. Vessels spotted in the camera image are flagged on the chart.
Options & settings:
| Control | What it does |
|---|---|
| Detection toggle | Enables AI camera-based vessel detection (YOLO model), fused with AIS targets. |
Tips & limits: - Requires a running detection server and an available camera feed. - Complements AIS rather than replacing it: useful for craft without a transponder.
Camera PiP
Camera PiP
What it's for: shows an IP camera feed as a picture-in-picture overlay on top of the chart, to watch the horizon or deck while keeping the map fullscreen.
How to use it: 1. Enable the Camera PiP row. 2. The video inset appears; the sidebar closes to free up a fullscreen map.
Options & settings:
| Control | What it does |
|---|---|
| Camera PiP toggle | Shows the IP camera video inset and switches to a fullscreen map. |
Tips & limits: - Uses the detection server (port 8044): the camera feed goes through that server. - Enabling this overlay automatically closes the sidebar to maximize chart area.