A.穩(wěn)定點(diǎn)B.起算點(diǎn)C.觀測點(diǎn)D.沉陷點(diǎn)
A.后視點(diǎn)高程B.前視點(diǎn)高程C.兩點(diǎn)的方位D.兩點(diǎn)的高差
A.90°B.30°C.150°D.270°