22 lines
555 B
Go
22 lines
555 B
Go
package langext
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import "math"
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func DegToRad(deg float64) float64 {
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return deg * (math.Pi / 180.0)
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}
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func RadToDeg(rad float64) float64 {
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return rad / (math.Pi * 180.0)
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}
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func GeoDistance(lon1 float64, lat1 float64, lon2 float64, lat2 float64) float64 {
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var d1 = DegToRad(lat1)
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var num1 = DegToRad(lon1)
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var d2 = DegToRad(lat2)
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var num2 = DegToRad(lon2) - num1
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var d3 = math.Pow(math.Sin((d2-d1)/2.0), 2.0) + math.Cos(d1)*math.Cos(d2)*math.Pow(math.Sin(num2/2.0), 2.0)
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return 6376500.0 * (2.0 * math.Atan2(math.Sqrt(d3), math.Sqrt(1.0-d3)))
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}
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