单项选择题
A polyconic projection is based on a （）.
A.plane tangent at one point
B.cylinder tangent at one parallel
C.cone tangent at one parallel
D.series of cones tangent at selected parallels
点击查看答案&解析
相关考题
-
单项选择题
A pilot vessel on pilotage duty at night will show sidelights and a stern light （）.
A.when at anchor
B.only when making way
C.at any time when underway
D.only when the identifying lights are not being shown -
单项选择题
A pilot vessel may continue to sound an identity signal if she is （）.
A.aground
B.at anchor
C.not under command
D.being towed -
单项选择题
A pilot chart does NOT contain information about （）.
A.average wind conditions
B.tidal currents
C.magnetic variation
D.average limits of field ice
