A line of levels is run from BM1 to BM2 that is 8 km long. Elevation of BM1 and BM2 was found out to be 155.50, and 142.94 m, respectively. The average backsight and foresight distances were 148, and 169, respectively. Determine the corrected elevation of BM2 considering the effect of curvature and refraction.  HINT: effect of curvature and refraction occurs on each rod reading.   NOTE: answer in two decimal places

In tacheometry survey, an intercept of 0.755m was recorded on a staff which was believed to vertical, and the vertical angle measured on the theodolite was +15º. Actually, the staff which was 4 metres long was 0.14m out of plumb bob and leaning backwards away from the instrument position. Assuming it was an anallatic instrument with a multiplying constant of 100, what would have been the error in the computed horizontal distance?

Imagine that you are the engineer responsible for the tacheometric survey of an area where a public park will be built. While surveying, you found a cliff that needs to be detailed mapped. Using a tacheometer, the following readings were obtained:Data:Zenith angle (z): 45°Reading on stadimetric wires:High wire: 1.485 mMedium yarn: 1,000 mLow wire:0.948 mInstrument height: 1.50mHeight of observed point: 0 m Calculate the horizontal distance from the observed point and the height of the cliff in relation to the instrument position. ∆d = 100. (A-B). cos²z∆h = Dx tan(z)+ (hm+hi-hv)- Give preference to make the resolution editable, handwriting hinders understanding.

definition of a datum in seismic reflection Choose one: a. a level equal to the mean-sea level b. all of the options are true c. a level were time is zero d. datum is the surface level of the earth