1) the third and fourth grade leveling
三、四等水准
1.
Conventional triangle elevation survey replacing the third and fourth grade leveling needs backsight distance equaling foresight distance to eliminate the influence of the earth curvature and observing bilaterally to reduce atmospheric refraction is considerable,which greatly increases field work.
常规的三角高程测量代替三、四等水准测量,要求保证前后视距相等来消除地球曲率的影响,要求对向观测来消除大气折光影响,大大增加了外业工作量。
3) fourth-grade-leveling
四等水准
1.
Precision analysis of triangle elevation survey of total station instrument to replace fourth-grade-leveling survey;
全站仪三角高程替代四等水准测量精度分析
5) national fourth-order leveling
国家四等水准
6) the 4th leveling surveying
四等水准测量
1.
It can conclude that the method can reach the precision for the 4th leveling surveying.
用中间法三角高程测量引测船排滑道放样高程基准点,阐述该方法的作业过程及精度,得出该方法可达到四等水准测量的精度要求。
补充资料：长等短等
1.犹言左等右等。谓等待久。
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条