# Arrow height

The arrow height , stitch height or just stitch has different meanings in different subject areas.

## Bridge building

The arrow height of the bridge at Limyra is 200 cm. Their arrow ratio is 1: 5.3 (200: 1065 cm).

In architecture , the arrow height is a measure of the distance between the fighter line and the apex of an arch . The quotient of the height of the arrow and the clearance is called the "arrow ratio" or "overvoltage". It is  1: 2 for a semicircle .

Other important dimensional relationships in bridge construction are the ratio of the pier thickness to the span and the arch thickness at the apex to the span. The daring number describes the ratio of the square of the wingspan to the height of the arrow.

## Curves

Arrow heights are also used as a control measure when measuring curved routes and other curves. The lateral distance between P 2 and the straight connection P 1 -P 3 is measured at three successive curve points P 1 , P 2 , P 3 . This allows the curvature of the curve to be checked in a simple manner.

## optics

In addition, the arrow height is used in technical optics to check the radius of lenses . In the measurement, the distance between the plane defined by a cutting edge placed on the lens surface and the height of the lens surface in the center of the cutting edge is measured here. The determination of the arrow height is an important measurement, especially for lenses that have not yet been polished, since the still matt surfaces are not accessible to conventional optical radius measurement methods.

## literature

• Bert Heinrich: Bridges. From beam to arch (= rororo 7711, rororo non-fiction book ). Rowohlt, Reinbek near Hamburg 1983, ISBN 3-499-17711-0 .

## Remarks

1. The values ​​for numerator and denominator are sometimes given in reverse.

## Individual evidence

1. ^ Bert Heinrich: Bridges. From beam to arch. 1983, p. 38.