单项选择题
A position that is obtained by applying estimated current and wind to your vessel’s course and speed is a(n) （）.
A.estimated position B.dead reckoning position C.fix D.None of the above
单项选择题 A position obtained by crossing lines of position taken at different times and advanced to a common time is a(n) （）.
单项选择题 A position obtained by applying ONLY your vessel’s course and speed to a known position is a （）.
单项选择题 A polyconic projection is based on a （）.
