a suggestion.. better to make public so everyone can use sample tests and avoiding re-invnetig the wheel.

[ingconti]

I see:
/// extension for convenience
private extension BinaryFloatingPoint {
/// degree converted to radians
var asRad: Self {
return rad(fromDegree: self)
}
var asDegrees: Self {
return deg(fromRadian: self)
}
var inNm: Self {
return nm(fromMeters: self)
}

}

better if public.. I suggest.

public extension BinaryFloatingPoint {

[dastrobu]

Thank you for your suggestion.
I have some doubts, though, making the extension public (and moving it from the test sources into the non-test sources).

An extension to a very general type like BinaryFloatingPoint floating point may pollute this type more than it helps. vincenty is a very special library solving exactly one thing. Conversion from meters to other units (like nautical miles) or from radians to degree or gradians is comparatively simple and people may have different approaches. For example there is the Units and Measurement API which has nauticalMiles and UnitAngle.

A nice improvement would be adding an example to the README, which shows usage of these conversion APIs. Would that make sense to you?