<P> and Coke's reversible level . Anyone of these can be used at a time for the purpose . </P> <Ul> <Li> Levelling Staff . </Li> <Li> Tripod stand </Li> </Ul> <Li> Levelling Staff . </Li> <P> RL of a survey point can be determined by two methods: - </P>

Why karachi is considered as the mean sea level for india