Cadastral, Topographic, and Construction Surveying
Cadastral framework
Ohio’s cadastral patterns include the PLSS in northwest Ohio and metes-and-bounds areas such as the Virginia Military District, Connecticut Western Reserve, and Symmes Purchase. Subdivision plats are governed by ORC Chapter 711; plats must be approved by the planning authority and recorded before lots are conveyed. A recorded plat, dedications, and monumented lot lines are the cadastral record.
Topographic and construction work
Topographic surveys show contours, spot elevations, breaklines, utilities, and planimetric features at a stated scale and contour interval. Construction surveys establish horizontal and vertical control, then set stakes by station and offset or by coordinates; as-built surveys verify location and elevation. Elevations must reference a stated datum, and layout must be checked by an independent inverse or second setup.
Worked example
Two cross sections for a proposed pad are 120 ft² and 180 ft², 50 ft apart. Average end area: (120 + 180) / 2 = 150 ft². Volume = 150 ft² × 50 ft = 7,500 ft³. Convert: 7,500 ÷ 27 = 277.8 yd³. Stating 278 yd³ is correct only if the sections are perpendicular to the alignment and no swell or shrink is applied.
Traps
Treating Virginia Military District or Western Reserve lands as PLSS; conveying lots before plat recording; using unverified assumed elevations; and computing volumes without checking end-area assumptions. Construction stakes also fail if the control network is not adjusted or if the design datum is misread.