Survey work starts with two fixed points. Markspan treats gross intake as the near abutment and platform fees as the far one. The span between them is the residual secondary earnings clearance.
Abutments on paper
Name both edges with the same instrument year. Without a clear far abutment, the span collapses into a vague remainder that cannot be checked.
What the span records
The span records distance after fees—not a plan for next week. It is a measuring mark, useful for reading a statement and useless as a pitch.
Return to the span index.