Topographic, Construction, and Engineering Surveys
What this domain tests
Questions cover mapping surface geometry, setting stakes that contractors can build from, and computing quantities and grades.
Core rules
- Contours are interpolated between spot elevations; breaklines control where interpolation is valid. Label index contours and state the contour interval on the drawing.
- Cut = existing ground minus proposed grade; fill = proposed minus existing. Sign conventions must be stated on the stake.
- Slope stakes locate the catch point where the design template meets existing ground; the offset and grade difference define the intercept.
- Volumes from average end areas: V = (A1 + A2)/2 × L. Convert cubic yards by dividing cubic feet by 27.
- ALTA/NSPS surveys follow the current Table A requirements; the certification and the items checked are part of the deliverable.
Worked example
Two cross sections 100 ft apart have areas of 120 sq ft and 80 sq ft. Volume = (120 + 80)/2 × 100 = 10,000 cu ft; 10,000/27 = 370.37 cu yd. At a stake where existing ground is 104.20 ft and proposed grade is 100.00 ft, the cut is 4.20 ft. Reasoning: subtract in the right order and state the convention; a reversed subtraction produces a fill that will be built wrong.
Traps that cost marks
- Using slope distance where horizontal distance is required.
- Confusing cut and fill signs on stakes.
- Ignoring shrinkage, compaction, or topsoil stripping in volume computations.
- Mixing site datum with NAVD88 elevations.
- Drawing smooth contours across a breakline.