Routing Overlays
Lay over the map every overlay tied to your active route: isochrones, comfort, cross-track corridor, laylines, tide gates, the ensemble route bundle, the coastal approach plan, routing barriers and the GRIB estimate.
Where to find it
Map › floating Overlays button (top-left) › Routing tab (route icon).
The Overlays panel is a draggable window. Click the Overlays button to open it, then pick the Routing tab in the category tab row. A badge on the tab shows how many overlays are active in that category.
Hierarchy
Overlays (floating panel)
├── Presets bar (save / load an overlay combo)
└── Routing tab
├── Isochrones
│ └── Sail Plan (appears under the button once a routing exists)
├── Comfort
├── XTD Corridor
├── Laylines
├── Tide Gates
├── Ensemble Routes
├── Coastal Approach
├── Barriers
│ └── Exclusion zones panel (draw / enable / delete)
└── GRIB estimate
└── Estimate panel (fixed heading / to destination · horizon)
Relationship with the Route tab
These overlays visualise on the map the results computed from the sidebar Route tab (route planning and isochrone routing). Most of them only display something when an active route exists, and some only once a routing has already been computed. Toggle an overlay here to lay the information on the chart; tune the routing parameters themselves in the Route tab.
Presets bar
What it's for: save a combination of enabled overlays (across all categories) under a name, to recall it with one click.
How to use it: 1. Enable the overlays you want. 2. Click the + (bookmark) icon on the left of the Presets bar. 3. Type a name (e.g. Transat, Coastal) and confirm. 4. To reload, click Presets and choose an entry from the list. The trash icon deletes a preset.
Tips & limits: a preset stores the state of all overlays, not only the Routing tab ones. The counter on the right shows how many active overlays are stored.
Isochrones
Isochrones
What it's for: show the weather-optimised route and the isochrone fronts (lines of equal travel time) computed from the Route tab. This is the chart visualisation of isochrone routing.
How to use it: 1. First run an isochrone routing from the Route tab (active route required). 2. Open Overlays › Routing and enable Isochrones. 3. The optimised route and fronts appear on the chart. 4. When a routing is available, a Sail Plan widget appears just under the button: it breaks the route into legs (point of sail, average TWA/TWS, duration). Hover a leg to highlight that segment on the chart.
Options & settings:
| Item | Effect |
|---|---|
| Isochrones button | Shows/hides the optimised route and isochrone fronts |
| Sail Plan widget | List of legs by point of sail; hover = highlight the segment on the chart |
Tips & limits: the computation itself (objectives fastest / safest / comfortable / balanced / least fuel, refinement, etc.) is set in the Route tab, not here. If the isochrone front did not converge on the destination, the displayed route stops short of arrival.
Comfort
Comfort
What it's for: colour the active route by a sailing comfort index (wave height, period, cross-sea) along the passage.
How to use it: 1. Make sure you have an active route. 2. Enable Comfort in the Routing tab. 3. The route is coloured by the expected comfort level.
Tips & limits: this overlay depends on real-time forecast data. In climatological mode (departure more than 7 days out) the button is greyed out with the message: Unavailable in climatological mode (departure >7 days). Requires real-time forecast or GRIB data. Load a GRIB or move the departure date closer to re-enable it.
XTD Corridor
XTD Corridor
What it's for: draw a cross-track distance corridor on either side of the active route, to visualise the acceptable margin before an off-track alert.
How to use it: 1. Have an active route. 2. Enable XTD Corridor. 3. The corridor boundaries appear along the route.
Options & settings:
| Context | Corridor width |
|---|---|
| Coastal | ±0.3 NM |
| Ocean | ±1.5 NM |
Tips & limits: the width adapts automatically to the context (coastal vs offshore). Handy to stay within a safe band during a landfall or a tight passage.
Laylines
Laylines
What it's for: show the optimal tack/gybe angles to reach the next waypoint upwind or downwind. A sailboat can't sail straight into the wind: stay on your current tack until your course crosses the layline — when you touch it, that's the optimal moment to tack (upwind) or gybe (downwind) to fetch the waypoint without losing distance.
How to use it: 1. Have an active route with a target waypoint. 2. Enable Laylines. 3. The tack/gybe lines and the uncertainty cone appear. Hover a line to read TWA and VMC.
Options & settings (colour key):
| Item | Meaning |
|---|---|
| Red line | Port tack |
| Green line | Starboard tack |
| Orange / cyan dashes | Gybes |
| Light cone | Wind uncertainty ±8° |
Tips & limits: the wind source can be the forecast (Open-Meteo) or onboard data (Signal K). A distance · time label between the boat and the layline marks when to tack. This overlay depends on real-time forecast data (greyed out in climatological mode).
Tide Gates
Tide Gates
What it's for: flag the favourable or adverse current windows at waypoints, so you can time your passage with the tide.
How to use it: 1. Have an active route. 2. Enable Tide Gates. 3. The current windows at the relevant waypoints appear.
Tips & limits: relies on NOAA tidal data, so it is mainly relevant in covered areas (United States). Essential for clearing a strong-current passage at the right moment.
Ensemble Routes
Ensemble Routes
What it's for: show a bundle of routes ("spaghetti") computed from the different members of the ensemble weather forecast, to visualise the spread and the robustness of the routing under uncertainty.
How to use it: 1. Have an active route. 2. Enable Ensemble Routes. 3. The route bundle from the ensemble members appears.
Tips & limits: relies on the ensemble members (ECMWF / GFS / ICON). A tight bundle means a robust routing; a scattered bundle signals strong weather uncertainty — be cautious about the departure window.
Coastal Approach
Coastal Approach
What it's for: generate a visual landfall plan near a harbour: transit bearings, leading lights and clearing lines for visual piloting.
How to use it: 1. Enable Coastal Approach. 2. Click on the map near a harbour / your destination to pick the approach target. 3. The plan is generated: marks, transits, leading lights and clearing lines.
Options & settings (generated plan panel):
| Item | Role |
|---|---|
| Radius | Extent of the analysed approach area |
| Amers (marks) | Detected visual landmarks |
| Transits / Top alignments | Recommended visual alignments |
| Leading lights | Lights useful on approach |
| Clearing lines | Clearing bearings (heuristic arcs) |
| Center | Re-centres the map on the target |
| Clear plan | Removes the generated plan |
Tips & limits: helper message Click on the map near a harbor to generate an approach plan. Clearing lines are heuristic arcs: validate them against the chart before use. This is a preparation aid, not a substitute for the paper chart or the official ENC.
Barriers
Barriers
What it's for: draw exclusion zones (polygons) the isochrone router must sail around: traffic-separation schemes (TSS), piracy corridors, ice limits, military/restricted areas, or simply water you want to avoid. Barriers are stored locally and apply to every future routing run (they aren't tied to one route).
How to use it: 1. Enable Barriers in the Routing tab. An Exclusion zones panel appears at the bottom-left of the map. 2. Click New barrier. 3. Click the map to drop each vertex (a counter shows; 3 vertices minimum). 4. Finish with a double-click or the Finish button. Cancel or Esc aborts. 5. Re-run routing from the Route tab: legs that enter an enabled barrier are rejected.
Options & settings:
| Element | Role |
|---|---|
| New barrier | Starts drawing a polygon. |
| Finish / Cancel | Closes or aborts the current drawing. |
| Eye (per zone) | Enable / disable. Disabled = drawn faded/dashed but ignored when routing. |
| Trash (per zone) | Delete the barrier. |
| Swatch + auto name | Each zone is named Zone 1, Zone 2… with its colour. |
Tips & limits: only enabled barriers with ≥ 3 vertices are honoured; avoidance applies on the next routing computation (main thread and Pareto workers). Barriers persist across sessions. A routing aid, not an official safety constraint.
GRIB estimate
GRIB estimate
What it's for: preview a dead-reckoning track. From a start point you drop on the map, the tool integrates your polar speed against the GRIB wind (varying in space and time) and draws a dashed cyan track with hourly markers. A what-if simulation tool, distinct from the live GPS-loss dead reckoning.
How to use it: 1. Enable GRIB estimate in the Routing tab. 2. Click the map to set the start point. 3. Pick the mode: Fixed heading (hold a constant course, typed in Heading °) or To destination (re-aims at the active route's destination each step, stops on arrival). 4. Set the Horizon h (1 to 240 h). 5. Read the track: each marker shows elapsed hours, boat speed (gear symbol when motoring), TWA and TWS. The panel sums total distance and ETA.
Options & settings:
| Element | Role |
|---|---|
| Fixed heading | Holds a constant compass course (Heading °, 0–359). |
| To destination | Chases the active route's destination (disabled without an active route with a destination). |
| Horizon h | Projection length (1–240 h). In "to destination" mode, reports "Not reached in {h}h — {nm} nm short". |
| Clear | Resets the start point. |
Tips & limits: needs a selected polar. Wind comes from the loaded GRIB (Source: loaded GRIB) or, failing that, the current static wind (Source: current wind). GRIB currents, if present, are added as set & drift. Speed is floored to 4.5 kn motoring when the polar can't drive the boat (head-to-wind, calm) — the same floor the isochrone engine uses. "To destination" is a straight rhumb-line chase, not the optimized isochrone route.