civ210

midterm 1

How do you estimate how far from the rod you are?

Lets say the top crosshair is on 6.00 and the bottom crosshair is on 4.00. You subtract the two, 6-4, which is 2. Then you multiply by 100. So the answer would be 200 ft

Gunther’s chain

66 ft long, 100 links, 22 lbs.

How long is one rod

1 rod = 16.5 ft, 2 rod = 33 ft, etc

Differential levelling steps

Step 1: Take back sight to a point that is known

Step 2: Establish height of instrument

Step 3: Next shot is foresight

Paralax

When you move your head when looking through the scope, the crosshairs move too, introducing error

Engineers tape

100 ft long, measured in ft, 10ths of ft, and 100ths of feet. Tape is calibrated

Chaining pins

Rear chain person has 7 chaining pins, that means the measurement is 700 ft plus whatever the last amount was

Difference between two stations

1+75 and 3+75. Difference is 200 ft

Right way to do differential and profile leveling

Step 1: Balance backsight and foresight

Step 2: Wave rod

Step 3: Communicate and confirm

Step 4: Write in notebook

Formula for HI, Elevation, and BS

HI = Elevation + BS

Difference between differential levelling and profile levelling

Differential leveling: HI, BS, FS and elev changes

Profile leveling: BS, HI stays the same, FS and elev change