User`s manual

6 ATMOSPHERE AND INSTRUMENTS
The wind value can be saved so that the estimate is restored next time XCSoar starts.
At any time during flight, the pilot can make corrections to the wind estimate by entering the cor-
rection in the wind settings dialog and pressing the Save Wind button. Once Save Wind is
pressed, the internal estimate is ignored until a new internal estimate is obtained from the circling
or zigzag algorithm.
The automatic wind algorithm and the compensation of wind drift of the trail may also be set in this
dialog.
6.6 Thermal locator
An algorithm estimates the center of the lift when circling. The thermal marker symbol is a green
circle with a ‘T’ in the center. The option ‘Lift center’ on the ‘Glide Computer’ page of the configu-
ration settings determines how this is used:
• OFF Lift center locator disabled.
• Circle at center A thermal marker is displayed at the center of lift.
• Pan to center A marker is displayed at the center of lift, and when circling, the display is panned
to this lift center.
When the thermal locator is enabled, the location of the last 20 thermals is marked on the map with
the thermal marker during cruise.
This location is calculated to compensate for the thermal drift at the glider’s height. This means that
internally XCSoar remembers the location of the thermal source on the ground. In other words, if
you leave a thermal at the top and later return at low altitude, the position on the map shows the
predicted location of the thermal at that low altitude (which is further upwind than the top).
If the wind changes and the thermal source is still active, its position on the map reflects the wind
change; that is, the thermal at altitude will be projected downwind at the new wind estimate.
61 XCSoar Manual (Altair version) • XCSoar-A-EN