Site pages
Current course
Participants
General
Topic 1
Topic 2
Topic 3
Topic 4
Topic 5
Topic 6
Topic 7
Topic 8
Topic 9
Topic 10
Topic 11
Topic 12
Topic 13
Topic 14
Topic 15
Topic 16
Topic 17
Topic 18
Topic 19
Topic 20
Topic 21
Topic 22
Topic 23
Topic 24
Topic 25
Topic 26
Topic 27
Topic 28
Topic 29
Topic 30
Topic 31
Topic 32
Experiment No 2 - Obstacle to chaining but not ranging
Practical - 2
Experiment No 2 - Obstacle to chaining but not ranging
Experiment No 2 - Obstacle to chaining but not ranging
There are two types of obstacle in this case
- When it is possible to chain round the obstacle. E.g., pond.
- When it is not possible to chain round the obstacle. E.g., river
When it is possible to chain round the obstacle
PQ is the chain line. Select two points A and B on either side of the obstacle. Setout equal perpendiculars AC and BD. Join CD and measure it. AB = CD.
When it is not possible to chain round the obstacle
AB is the chain line. Select a point ‘C’ on the line and draw perpendicular CD to it. Bisect it at E. Erect a perpendicular to the line CD at ‘D’. Range ‘F’ in line with GE and measure DF. Then GC = DF.
PQ is the chain line. Select two points A and B on either side of the obstacle. Setout equal perpendiculars AC and BD. Join CD and measure it. AB = CD.
When it is not possible to chain round the obstacle
AB is the chain line. Select a point ‘C’ on the line and draw perpendicular CD to it. Bisect it at E. Erect a perpendicular to the line CD at ‘D’. Range ‘F’ in line with GE and measure DF. Then GC = DF.
Last modified: Tuesday, 19 April 2011, 10:50 AM