Figure 5. Graphical representation of the output from Perim.m. (A) Smaller conduits are surveyed along one line. Thirty-six interpolated points are created along the cross-sectional perimeter of a conduit (assumed to be an irregular polygon) at each associated survey station. (B) Very large conduits are commonly surveyed along two or more lines creating multiple sets of cross-sectional points at each associated station. Thirty interpolated points are created along the cross-sectional perimeter of the conduit (assumed to be a rectangle) at each associated survey station.