The Unofficial XCSoar Manual
Faq:SafetyHeights
From XCSoar
Contents |
What is the 'Terrain Safety Height'?
Terrain safety height is the height above terrain at which XCSoar considers you're too low to cross. This is only used in calculating the final glide through terrain and glide reach.
What is the 'Arrival Safety Height'?
Arrival height is the height above the landpoint that you would which to arrive in a cross-country task. For example, many people set this at a safe circuit joining height plus maybe a small margin.
What is the 'Break-off Safety Height'?
Break-off height is the height above terrain when flying cross-country, below which you should be looking for airfields or outlanding options. XCSoar doesn't do very much with this just yet.
How does XCSoar determine my height?
This depends on the 'Nav by baro altitude' setting on Page 3 (Glide Computer) of Setup System.
- OFF: Height is determined by GPS altitude alone.
- ON: The height is provided by a barometric altimeter (if available).
Where XCSoar is used with the Vega variometer, QNH compensation is performed automatically by setting the QNH such that the barometric altitude equals the terrain altitude when on the ground. Due to the limited resolution of the terrain data as explained above, this itself can result in a small offset error.
