Civil Engineering - Surveying - Discussion
Discussion Forum : Surveying - Section 2 (Q.No. 15)
15.
A dumpy level was set up at the midpoint between two pegs A and B, 50 m apart and the staff readings at A and B were 1.22 and 1.06. With the level set up a A, the readings at A and B were 1.55 and 1.37. The collimation error per 100 m length of sight is
Discussion:
20 comments Page 1 of 2.
M.Pagavan doss said:
1 decade ago
Distance between a and b = 50 m.
When instrument at center=1.22 - 1.06 = .160.
When instrument near A = 1.55-1.37 = .180.
DIFF = .160-.180 = -.020(- INDICATE DOWNWARDS).
COLLIMATION ERROR FOR 100M length = (.020/50)*100 = .04m inclined downward.
When instrument at center=1.22 - 1.06 = .160.
When instrument near A = 1.55-1.37 = .180.
DIFF = .160-.180 = -.020(- INDICATE DOWNWARDS).
COLLIMATION ERROR FOR 100M length = (.020/50)*100 = .04m inclined downward.
(1)
Sammy said:
9 years ago
Best explanation.
Thanks @M.Pagavan Doss.
Thanks @M.Pagavan Doss.
MD SADDAM said:
9 years ago
Please help about B.O.D & C.O.D formula.
DARSHAN said:
9 years ago
Here when you put level at centre all errors are eliminated .
Hence difference in RL is 1.22 - 1.06 is 0.16 but the observed staff difference is 1.55 - 1.37 = 0.180.
Therefore the error is 0.180 - 0.160 = 0.02 for 50 m, for 100m it is 0.04. It is positive value hence line of sight is upwards.
Hence difference in RL is 1.22 - 1.06 is 0.16 but the observed staff difference is 1.55 - 1.37 = 0.180.
Therefore the error is 0.180 - 0.160 = 0.02 for 50 m, for 100m it is 0.04. It is positive value hence line of sight is upwards.
(1)
Ashok said:
9 years ago
When the level is not set at the center what distance can I take instead of 50m?
Swapnil said:
9 years ago
Thanks for explaining easily.
Aarti Nepal said:
9 years ago
Thank you so much @M.Pagavan Doss.
SANDEEP said:
9 years ago
Thank you @Pagavan Doss.
Sooraj said:
9 years ago
Thank you so much @Pagavan Doss.
Deep said:
7 years ago
Formula of errors =(b1-a1)-(b2-a2)/2.
Now, e = (1.06-1.22)-(1.37-1.55)/2 =0.01for 50 m and for 100 m error = 2 *0.01 = 0.02 upward.
Now, e = (1.06-1.22)-(1.37-1.55)/2 =0.01for 50 m and for 100 m error = 2 *0.01 = 0.02 upward.
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