/// <summary>
/// Returns the center point of the specified <paramref name="line"/>.
///
/// The center point is calculated by travelling half of the line's total length.
/// </summary>
/// <param name="line">The line.</param>
/// <returns>An instance of <see cref="IPoint"/> representing the center point.</returns>
/// <exception cref="ArgumentNullException"><paramref name="line"/> is <c>null</c>.</exception>
public static IPoint GetCenter(ILineString line)
{
if (line == null)
{
throw new ArgumentNullException(nameof(line));
}
double distance = GetLength(line.Points) / 2d;
for (int i = 1; i < line.Points.Length; i++)
{
IPoint a = line.Points[i - 1];
IPoint b = line.Points[i];
double d = DistanceUtils.GetDistance(a, b);
if (d > distance)
{
// Caculate the heading between "a" and "b" (the center is on that line)
double heading = ComputeHeading(a, b);
// Calculate the offset/center based on the remaining distance
return(ComputeOffset(a, distance, heading));
}
distance -= d;
}
return(line.GetBoundingBox().GetCenter());
}
/// <summary>
/// Returns the length of the line or line string represented by the specified <paramref name="points"/>.
/// </summary>
/// <param name="points">The points making up the line.</param>
/// <returns>The length in metres.</returns>
/// <exception cref="ArgumentNullException"><paramref name="points"/> is <c>null</c>.</exception>
public static double GetLength(IPoint[] points)
{
if (points == null)
{
throw new ArgumentNullException(nameof(points));
}
double sum = 0;
// Iterate through each point in the path (skip the first point)
for (int i = 1; i < points.Length; i++)
{
// Calculate the distance between the two points
sum += DistanceUtils.GetDistance(points[i - 1], points[i]);
}
return(sum);
}
/// <summary>
/// Returns the circumference of the closed path represented by the specified <paramref name="points"/>.
/// </summary>
/// <param name="points">The points making up the closed path.</param>
/// <param name="radius">The radius of the spheroid.</param>
/// <returns>The circumference in metres.</returns>
/// <exception cref="ArgumentNullException"><paramref name="points"/> is <c>null</c>.</exception>
public static double GetCircumference(IPoint[] points, double radius)
{
if (points == null)
{
throw new ArgumentNullException(nameof(points));
}
double sum = 0;
// Iterate through each point in the path
for (int i = 0; i < points.Length; i++)
{
// While "i" is the index of the first point and "j" is the second point
int j = i == 0 ? points.Length - 1 : i - 1;
// Calculate the distance between the two points
sum += DistanceUtils.GetDistance(points[i], points[j], radius);
}
return(sum);
}
