Study your routing and pivot points

Expert

The essentials

A calculated routing is more than a line on the chart: you can read it back, then restart from one of its points to test another option.

A pivot point is a point on an isochrone through which a new routing is forced to pass. It is the quickest way to compare two options, for example passing inside or outside a traffic separation scheme.

Going further

Study a routing that is already calculated

To read a routing back, follow the boat along the route, the leg-by-leg table, the statistics and the calculation inputs: all of this is described in Read a routing. Routings are found and managed in the “Routings” tab: see Manage routings.

The isochrones show where the boat can be at each time step. On each one, a blue dot marks the point through which the best route passes. If the route does not pass through it, it is the point closest to the finish, in distance over water. These points serve as pivot points to test another route option. See Routing principles and isochrones.

Route from a pivot point

A pivot point is a point on an isochrone through which a new routing is forced to pass. It is the quickest way to compare two options, for example passing inside or outside a traffic separation scheme.

Display the routing’s isochrones (“Isochrones” checkbox in the layers menu, then tap the routing in the “Routings” tab): see Routing principles and isochrones.
Choose the point:
- on computer, move the mouse: the optimal route to the nearest isochrone point is displayed. Click that point, then “Routing from this point”;
- on tablet and phone, move the chart: the point follows the target at the centre of the screen. Then tap “+”: the “Calculate Routing” entry there becomes “Routing from this point”.
The new routing starts from the chosen routing at the pivot point and continues to the finish.

A routing from a pivot point takes its route, start time and weather files from the chosen routing, not those set in the “Routing” window. It is refused if those files are no longer on the device, or if they have been updated with a more recent forecast: the two pieces of route would then come from two different forecasts. The message invites you to recalculate the routing first.

Good to know

The isochrone time step restarts from the pivot point (see Routing principles and isochrones).
The best start search does not apply to a routing from a pivot point, which necessarily starts at the time of its point (see Best start).
On tablet and phone, the point follows the target: see Navigation tools on the chart.