HaversineDistance

Haversine Distance

Haversine距离

Calculates the distance on a sphere between two points given in latitude and longitude using the haversine formula. 使用半正公式计算纬度和经度给出的两点之间的球体距离。

The haversine formula can be found on Wikipedia Haversine formula的维基百科

The Haversine Distance is implemented as a function as a class would be kind of overkill. Haversine Distance实现为一个函数，因为类会有点矫枉过正。

haversineDinstance(la1: Double, lo1: Double, la2: Double, lo2: Double, radius: Double = 6367444.7) -> Double

• la1 is the latitude of point 1 in degrees.

• lo1 is the longitude of point 1 in degrees.

• la2 is the latitude of point 2 in degrees.

• lo2 is the longitude of point 2 in degrees.

• radius is the radius of the sphere considered in meters, which defaults to the mean radius of the earth (from WolframAlpha).

• la1是点1的纬度（以度为单位）。

• lo1是度数为1的经度。

• la2是以度为单位的第2点的纬度。

• lo2是度数为2的经度。

• radius是以米为单位的球体半径，默认为地球的平均半径（来自WolframAlpha）。

The function contains 3 closures in order to make the code more readable and comparable to the Haversine formula given by the Wikipedia page mentioned above.

1. haversine implements the haversine, a trigonometric function.
2. ahaversine the inverse function of the haversine.
3. dToR a closure converting degrees to radians.

The result of haversineDistance is returned in meters.

该函数包含3个闭包，以使代码更具可读性，并与上面提到的Wikipedia页面给出的Haversine公式相当。

1. hasrsine实现了三角函数hasrsine。
2. ahaversinethersine的反函数。
3. dToR一个将度数转换为弧度的闭包。

hasrsineDistance的结果以米为单位返回。

Written for Swift Algorithm Club by Jaap Wijnen.

作者：Jaap Wijnen
翻译：Andy Ron