This standard refers to deviation of a 10-foot straightedge by making use of the computer software.

The computer software simulate moving an imaginary 10-foot straightedge along a profile line.

For each simulated placement of the straightedge, the software finds the two high points at least two data points apart on which gravity will permit the straightedge to rest.

 

10-foot straightedge

The program then determines the vertical deviation of the floor from the straightedge for all survey points between the high points.

Deviations are calculated only between the support points, not from cantilevered ends of the simulated straightedge.