/// <summary>
/// Is loop clockwise normalized?
/// </summary>
/// <param name="loop"></param>
/// <param name="isTransmeridian"></param>
/// <returns></returns>
private static bool IsClockwiseNormalized(this LinkedGeoLoop loop, bool isTransmeridian)
{
var sum = 0m;
var nodes = loop.Nodes;
for (var idx = 0; idx < nodes.Count; idx++)
{
var a = nodes[idx];
var b = nodes[(idx + 1) % nodes.Count];
// If we identify a transmeridian arc (> 180 degrees longitude),
// start over with the transmeridian flag set
if (!isTransmeridian && Math.Abs(a.Longitude - b.Longitude) > Constants.H3.M_PI)
{
return(loop.IsClockwiseNormalized(true));
}
sum += (b.Longitude.NormalizeLongitude(isTransmeridian) -
a.Longitude.NormalizeLongitude(isTransmeridian)) *
(b.Latitude + a.Latitude);
}
return(sum > 0);
}
/// <summary>
/// Is loop clockwise?
/// </summary>
/// <param name="loop"></param>
/// <returns></returns>
public static bool IsClockwise(this LinkedGeoLoop loop)
{
return(loop.IsClockwiseNormalized(false));
}
