Glossary of terms

Elevation

Elevation is the height of a point relative to an adopted vertical datum, usually expressed in metres. In a longitudinal profile you mainly use ground elevation and pipe or channel invert elevation; their difference at a given point is the installation depth. Invert elevations at consecutive nodes define the slope of a section. A clear profile gives elevations at characteristic points such as manholes, route bends and crossings. When checking a design, compare ground elevations with survey data and confirm that invert levels fall in the direction of flow.