20 lines
736 B
C#
20 lines
736 B
C#
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namespace JobsMedical.Web.Services;
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public static class Geo
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{
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private const double EarthRadiusKm = 6371.0;
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/// <summary>Great-circle (Haversine) distance in kilometers between two lat/lng points.</summary>
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public static double DistanceKm(double lat1, double lng1, double lat2, double lng2)
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{
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double dLat = ToRad(lat2 - lat1);
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double dLng = ToRad(lng2 - lng1);
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double a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2)
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+ Math.Cos(ToRad(lat1)) * Math.Cos(ToRad(lat2))
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* Math.Sin(dLng / 2) * Math.Sin(dLng / 2);
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return EarthRadiusKm * 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
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}
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private static double ToRad(double deg) => deg * Math.PI / 180.0;
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}
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