Using Rise / Fall Method
In this method booking is done in the following manner,
| B.S | I.S | F.S | Rise | Fall | R.L | Remarks |
|---|---|---|---|---|---|---|
| 2.570 | – | – | – | – | 100.00 | A |
| 3.750 | – | 1.200 | 1.370 | – | 101.37 | C.P |
| – | – | 3.750 | – | 0.70 | 100.67 | B |
| 5.620 | – | 4.950 | 1.370 | 0.70 | – | – |
- On any page of book the first reading is always a B.S and last reading is always a F.S. If you are not getting F.S as last reading on each page then it means you have done mistake while booking readings.
- From the B.S next F.S is subtracted. If the answer is +ve it will be Rise and if the answer is -ve it be Fall and put that reading in respective box.
- In the above table, I have assumed that Reduce Level (R.L) of point A is 100.0 and you can see R.L of point B is 100.67, which shows that point B is .67 units higher than point A.
In case of numerous readings the check should be applied at the end of each page while booking reading,
∑ (B.S) – ∑ (F.S) = ∑ Rise – ∑ Fall = R.L of last point – R.L of first point 5.620 – 4.950 = 1.37 – 0.70 = 100.67 – 100 0.67 = 0.67 = 0.67
Using Height of collimation Method (H.O.C)
For this method use the following formulas,
R.L + B.S = H.O.C and H.O.C – F.S = R.L
| B.S | I.S | F.S | H.O.C | R.L | Remarks |
|---|---|---|---|---|---|
| 2.50 | – | – | 102.50 | 100.00 | – |
| 1.75 | 1 | 1.95 | 102.30 | 100.55 | – |
| – | 2.55 | – | – | 99.75 | – |
| – | 2.70 | – | – | 99.60 | – |
| 2.95 | – | 3.10 | – | 99.20 | – |
| – | – | 2.75 | – | 99.40 | – |
| 7.20 | – | 7.80 | – | – | – |
All other considerations are same as Rise/ Fall method. Below check have applied,
∑ (B.S) – ∑ (F.S) = R.L of last point – R.L of first point = 7.2 – 7.8 = 99.4 – 100 = -0.6 = -0.6
