1.15.5.b. Height of Instrument method

Try these first

1. 1.

   What does HI stand for in surveying?

   Hint

   Think of what gives us the elevation point.

2. 2.

   How do you determine the HI?

   Hint

   Remember, it’s like building upon a known point.

3. 3.

   What is the formula for calculating the Height of Instrument?

   • HI = RL of BM + BS
   • HI = BS - RL of BM
   • HI = RL of BM - FS

   Hint

   It's about adding the back sight reading.

4. 4.

   True or False: The Height of Instrument method includes checks for intermediate elevations.

   • True
   • False

   Hint

   Consider the limitations we've talked about.

5. 5.

   A surveyor records a benchmark at 75.50m. They measure a BS of 2.75m. If the FS reading at the next station is 1.95m, determine the complete elevation of the point surveyed.

   Hint

   Use each step of HI properly to find RL.

6. 6.

   Explain how making errors in BS measurements can affect the final point RL in the Height of Instrument method.

   Hint

   Consider the implications of foundational accuracy in surveying.