> For the complete documentation index, see [llms.txt](https://docs.estela.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.estela.co/tracking-races-with-estela/rounding-directions-and-waypoints.md).

# Rounding Directions and Waypoints

eStela uses three types of marks to define race courses:

* Rounding Buoys
* Waypoints
* Doors

Each type has a specific role in tracking, visualization, and race analytics.

### Rounding Buoys

Rounding buoys are physical marks that boats are required to round. eStela automatically detects whether a boat rounds the buoy correctly based on direction.

* The **system calculates the rounding direction automatically** based on the previous and next mark in the course.
* If the angle between the approach and departure is narrow, both directions are accepted.
* You cannot manually set the rounding direction.
* These marks are included in:
  * Time tables
  * Boat performance analytics

Use rounding buoys to define required rounding points in the race.

#### Forcing a rounding direction with waypoints

Because the direction comes from the geometry of the course, the way to "force" a specific rounding direction is to change that geometry: **add a waypoint between the marks**, on the side the boats are meant to sail.

The waypoint changes the bearing from which boats approach the buoy (or the bearing at which they leave it), so the angle between the incoming and outgoing legs becomes unambiguous and eStela resolves the rounding to the direction you intended.

This is the recommended fix when:

* The approach and departure legs are almost aligned, so both directions are accepted and roundings are validated on the wrong side.
* The course doubles back on itself and the automatic calculation picks the opposite side to the sailing instructions.

Practical tips:

* Place the waypoint clearly offset to the side the boats will pass, not on the straight line between the two marks.
* One waypoint before the buoy is usually enough; add a second one after it if the departure leg is also ambiguous.
* Waypoints do not need to be rounded or crossed by the boats and do not appear in time tables, so they change the rounding calculation without affecting results or analytics.

### Waypoints

Waypoints are virtual marks that boats are not expected to round. They are mainly used for visualization and distance calculation.

* Waypoints help shape the course for metrics like total distance
* Boats do not need to cross or round them
* They are not shown in time tables or performance metrics
* They cannot be selected during replay or live visualization
* They can be used to force the rounding direction of a nearby rounding buoy (see above)

Waypoints are especially useful for coastal or offshore courses, where visualizing the intended route is helpful, even if some points aren't actual rounding marks.

### Doors

Doors are imaginary lines created between two marks. A door is considered crossed when a boat sails through the line in the correct direction, which is also automatically calculated based on the course flow.

* Commonly used for:
  * Start lines
  * Finish lines
  * Mid-course gates (e.g. in windward-leeward layouts)

Like rounding buoys, door crossings contribute to timing and classification features.