/// <summary>
/// Normalizes a <c>LineString</c>. A normalized <c>LineString</c>
/// has the first point which is not equal to it's reflected point
/// less than the reflected point.
/// </summary>
public override void Normalize()
{
for (int i = 0; i < _points.Count / 2; i++)
{
int j = _points.Count - 1 - i;
// skip equal points on both ends
if (!_points.GetCoordinate(i).Equals(_points.GetCoordinate(j)))
{
if (_points.GetCoordinate(i).CompareTo(_points.GetCoordinate(j)) > 0)
{
var copy = _points.Copy();
CoordinateSequences.Reverse(copy);
_points = copy;
}
return;
}
}
}
/// <summary>
/// Creates a <c>LinearRing</c> using the given <c>CoordinateSequence</c>; a null or empty CoordinateSequence
/// creates an empty LinearRing. The points must form a closed and simple
/// linestring. Consecutive points must not be equal.
/// </summary>
/// <param name="coordinates">A CoordinateSequence (possibly empty), or null.</param>
/// <returns>A <see cref="LinearRing"/> object</returns>
/// <exception cref="ArgumentException"> If the ring is not closed, or has too few points</exception>
public virtual LinearRing CreateLinearRing(CoordinateSequence coordinates)
{
return(new LinearRing(coordinates, this));
}
/// <summary>
/// Constructs a <c>Polygon</c> with the given exterior boundary.
/// </summary>
/// <param name="coordinates">the outer boundary of the new <c>Polygon</c>, or
/// <c>null</c> or an empty <c>LinearRing</c> if
/// the empty geometry is to be created.</param>
/// <returns>A <see cref="Polygon"/> object</returns>
/// <exception cref="ArgumentException">If the boundary ring is invalid</exception>
public virtual Polygon CreatePolygon(CoordinateSequence coordinates)
{
return(CreatePolygon(CreateLinearRing(coordinates)));
}
/// <summary>
/// Shifts the positions of the coordinates until the coordinate at <code>firstCoordinateIndex</code>
/// is first.
/// </summary>
/// <param name="seq">The coordinate sequence to rearrange</param>
/// <param name="indexOfFirstCoordinate">The index of the coordinate to make first</param>
public static void Scroll(CoordinateSequence seq, int indexOfFirstCoordinate)
{
Scroll(seq, indexOfFirstCoordinate, IsRing(seq));
}
/// <summary>
/// Creates a <c>Point</c> using the given <c>CoordinateSequence</c>; a null or empty
/// CoordinateSequence will create an empty Point.
/// </summary>
/// <param name="coordinates">a CoordinateSequence (possibly empty), or null</param>
/// <returns>A <see cref="Point"/> object</returns>
public virtual Point CreatePoint(CoordinateSequence coordinates)
{
return(new Point(coordinates, this));
}
private static CoordinateSequence CreateClosedRing(CoordinateSequenceFactory fact, CoordinateSequence seq, int size)
{
var newseq = fact.Create(size, seq.Dimension);
int n = seq.Count;
Copy(seq, 0, newseq, 0, n);
// fill remaining coordinates with start point
for (int i = n; i < size; i++)
{
Copy(seq, 0, newseq, i, 1);
}
return(newseq);
}
/// <summary>
/// Returns the index of the minimum coordinate of the whole
/// coordinate sequence, using the usual lexicographic comparison.
/// </summary>
/// <param name="seq">The coordinate sequence to search</param>
/// <param name="from">The lower search index</param>
/// <param name="to">The upper search index</param>
/// <returns>The index of the minimum coordinate in the sequence, found using <see cref="Coordinate.CompareTo(Coordinate)"/></returns>
public static int MinCoordinateIndex(CoordinateSequence seq)
{
return(MinCoordinateIndex(seq, 0, seq.Count - 1));
}
/// <summary>
/// Ensures that a CoordinateSequence forms a valid ring,
/// returning a new closed sequence of the correct length if required.
/// If the input sequence is already a valid ring, it is returned
/// without modification.
/// If the input sequence is too short or is not closed,
/// it is extended with one or more copies of the start point.
/// </summary>
/// <param name="fact">The CoordinateSequenceFactory to use to create the new sequence</param>
/// <param name="seq">The sequence to test</param>
/// <returns>The original sequence, if it was a valid ring, or a new sequence which is valid.</returns>
public static CoordinateSequence EnsureValidRing(CoordinateSequenceFactory fact, CoordinateSequence seq)
{
int n = seq.Count;
// empty sequence is valid
if (n == 0)
{
return(seq);
}
// too short - make a new one
if (n <= 3)
{
return(CreateClosedRing(fact, seq, 4));
}
bool isClosed = seq.GetOrdinate(0, 0) == seq.GetOrdinate(n - 1, 0) &&
seq.GetOrdinate(0, 1) == seq.GetOrdinate(n - 1, 1);
if (isClosed)
{
return(seq);
}
// make a new closed ring
return(CreateClosedRing(fact, seq, n + 1));
}
/// <inheritdoc/>
/// <remarks>
/// The <see cref="Polygon.ExteriorRing"/> is guaranteed to be orientated counter-clockwise.
/// </remarks>
public override Polygon CreatePolygon(CoordinateSequence coordinates)
{
var ring = CreateLinearRing(coordinates, true);
return(base.CreatePolygon(ring));
}
public ReversedCoordinateSequence(CoordinateSequence inner)
: base(inner.Count, inner.Dimension, inner.Measures)
{
_inner = inner;
}
/// <inheritdoc cref="Geometry.CopyInternal"/>>
protected override Geometry CopyInternal()
{
return(new LinearRing(CoordinateSequence.Copy(), Factory));
}
/// <summary>
/// Constructs a <c>LinearRing</c> with the vertices specified
/// by the given <see cref="CoordinateSequence"/>.
/// </summary>
/// <param name="points">A sequence points forming a closed and simple linestring,
/// or <c>null</c> to create the empty geometry.</param>
/// <param name="factory">The factory that creates this <c>LinearRing</c></param>
/// <exception cref="ArgumentException">If the ring is not closed, or has too few points</exception>
public LinearRing(CoordinateSequence points, GeometryFactory factory)
: base(points, factory)
{
ValidateConstruction();
}
