A topographical survey records site levels and the positions of hard features, commonly using GPS coordinates referenced to OSGB36.

Height information above sea level is collected as standard. A 3D topographical survey displays this data at the correct height within the model space, often using 3D polylines. Each surveyed point therefore has an X and Y horizontal reference and a Z vertical reference.

Your project designers will normally specify whether a 3D topographical survey is required. Most topographical surveys are now completed in 3D because the additional height information supports modern design and modelling workflows.

A 3D topographical survey typically includes an AutoCAD DWG model and a PDF copy. An accompanying survey report can also be supplied when requested.

Yes. GEOTEC prefers to complete topographical surveys alongside underground mapping surveys.

Underground findings are recorded topographically as part of the mapping process, so completing both surveys at the same time is usually more efficient.

In a 3D topographical survey, each surveyed point is displayed at its correct Z value—or vertical height—within the model space and features can be represented using 3D polylines.

In a 2D topographical survey, the points are generally displayed with a zero Z value.

It depends on what is being surveyed and the level of detail required. In most cases, 3D laser scanning is not necessary for a standard 3D topographical survey.