Degree of curvature

The degree of curvature is defined as the central angle to the ends of an agreed length of either an arc or a chord;[1] various lengths are commonly used in different areas of practice.

This angle is also the change in forward direction as that portion of the curve is traveled.

In an n-degree curve, the forward bearing changes by n degrees over the standard length of arc or chord.

A small circle can be easily laid out by just using radius of curvature, but degree of curvature is more convenient for calculating and laying out the curve if the radius is as large as a kilometer or mile, as is needed for large scale works like roads and railroads.

By using degrees of curvature, curve setting can be easily done with the help of a transit or theodolite and a chain, tape, or rope of a prescribed length.

The usual distance used to compute degree of curvature in North American road work is 100 feet (30.5 m) of arc.

[2][page needed] Conversely, North American railroad work traditionally used 100 feet of chord, which is used in other places[where?]

Since rail routes have very large radii, they are laid out in chords, as the difference to the arc is inconsequential; this made work easier before electronic calculators became available.

Metric work may use similar notation, such as kilometers plus meters 1+000.

is degree of curvature, arc definition Substitute deflection angle for degree of curvature or make arc length equal to 100 feet.