Topographic and as-built survey

What it is

A conformance check asks one question: is the built surface within tolerance of the design surface? Answering it needs a measured surface dense enough that the answer is not an interpolation between rover shots twenty metres apart. Aerial capture gives a point every twelve millimetres, and breaklines drawn where the landform actually breaks.

Specification

The numbers, published

Accuracies are 1σ residuals measured at independent checkpoints excluded from the adjustment. Every figure on this page is invented for a demonstration build.

Method

How we do it

• Breaklines are drawn, not derived

  Crests, toes, kerb lines and drainage inverts are picked as breaklines rather than left to a contouring algorithm. A contour set generated straight off a point cloud looks fine and rounds off every edge that matters.

• Your format, your datum, before we deliver

  DXF or 12da, layer naming to your standard, GDA2020 / MGA Zone 50 with AHD heights unless you specify otherwise. Agreed at quote, not discovered at delivery.

• Checked against the design

  Where a design surface is supplied, we return a cut/fill comparison against it — so the conformance answer arrives with the survey rather than a week later.