Obstacle to chaining and ranging - Obstacle to ranging but not chaining

Unit 1- Surveying

Chain surveying
Obstacle to chaining and ranging

Obstacle to ranging but not chaining
In this type of obstacle, the ends are not intervisible and are quite common, except in a flat country.

Fig1

AB is the line in which A and B are not visible from intermediate point on it. Through A, draw a random line AB1 in any convenient direction but as nearly towards B as possible. The point B1 should be chosen in such a way that B1 is visible from B and BB1 is perpendicular to the random line. Measure BB1. Select C1 and D1 on the random line and erect perpendicular C1C and D1D on it. Join CD and prolong.

Fig2
Last modified: Friday, 29 April 2011, 6:45 AM