A.豎軸 B.圓水準(zhǔn)器 C.水準(zhǔn)管軸 D.水準(zhǔn)器
水準(zhǔn)儀有DS0.5、DS1、DS3等多種型號(hào),其下標(biāo)數(shù)字0.5、1、3等代表水準(zhǔn)儀的精度,為水準(zhǔn)測(cè)量每公里往返高差中數(shù)的中誤差值,單位為:()
A.km B.m C.cm D.mm
M點(diǎn)高程Hm=43.251m,測(cè)得后視讀數(shù)a=1.000m,前視讀數(shù)b=2.283m。則N點(diǎn)對(duì)M點(diǎn)的高差hMN和待求點(diǎn)N的高程HN分別為:()
A.1.283m,44.534m B.-3.283m,39.968m C.3.283m,46.534m D.-1.283m,41.968m