Degree of curvature

Degree of curve or degree of curvature is a measure of curvature used in civil engineering for its easy use in layout surveying.

A n-degree curve turns n degrees over some agreed-upon distance. The usual distance is 100 ft of chord, but 100 ft of arc is also common, and other lengths&mdash;such as 100 metres where SI is favoured, or a shorter length for sharper curves.

The 100 ft is a station, used to define length along an alignment. Annotated as 1+00, 2+00 etc.

Typically roads are defined in arcs, and since rail routes have very large radii, they are laid out in chords, as the difference to the arc is inconsequential.

Beware though, the degree of curvature, as typically defined in civil literature, is for a 100' chord.