Setting out and the spot-level survey are two complementary, fundamental measurement tasks in the construction process. Simply put: the spot-level survey measures the existing ground to feed the design, while setting out carries the design’s points onto the site. When both are done correctly, the structure sits in its place on paper with millimetre fidelity.
Spot-level survey: reading the ground
A spot-level survey is the numerical capture of an area’s existing surface together with its level (height) information. It shows the real ground the design will sit on.
A project prepared without a spot-level survey cannot see the slope and level differences on site; this leads to cut-and-fill imbalance, drainage problems and later revision. A correct spot-level survey enables:
- the correct planning of excavation and fill volumes,
- level and slope decisions made against the real ground,
- correct set-up of infrastructure and drainage design.
Setting out: carrying the design onto the site
Setting out (control-point application) is the precise marking on site, in their real positions, of the axis, corner and level points defined in the design. Every stage, from the foundation of the structure to steel installation, relies on correctly set-out references.
A faulty setting out means a foundation dug in the wrong place, a misaligned axis or a mismatched installation. Such errors require very costly later corrections. That is why setting out is done with a high-precision total station and GNSS.
The difference between the two
- Spot-level survey → from site to design (measures the existing state).
- Setting out → from design to site (carries the design onto the ground).
In a construction process the spot-level survey is usually taken first, the design is made accordingly, and then the project is applied to the site by setting out.
The role of correct measurement
Both tasks rely on a controlled reference network and disciplined measurement. AKPRO carries out its spot-level survey and setting out work to the precision needed for the site to progress at the correct level and position. This way, the cost of a measurement error is removed before work even begins on site.