单项选择题
A chart projection depicting the poles and a small area on either side of a connecting meridian，that is sometimes used for star charts，is the（）.
A.Azimuthal gnomonic projection B.Lambert conformal projection C.Transverse Mercator projection D.Polyconic projection
单项选择题 A chart position enclosed by a square is a（n）（）.
单项选择题 （）is not a position-fixing system.
单项选择题 Which aid is NOT marked on a chart with a magenta circle? （）
