/// <summary> Gets a location which refers to the end of a linear <see cref="Geometry"/>.</summary>
/// <param name="linear">the linear geometry
/// </param>
/// <returns> a new <tt>LinearLocation</tt>
/// </returns>
public static LinearLocation GetEndLocation(Geometry linear)
{
// assert: linear is LineString or MultiLineString
LinearLocation loc = new LinearLocation();
loc.SetToEnd(linear);
return(loc);
}
/// <summary>
/// Assumes input is valid (e.g. start <= end)
/// </summary>
/// <param name="start">
/// </param>
/// <param name="end">
/// </param>
/// <returns>A linear geometry.</returns>
private LineString ComputeLine(LinearLocation start, LinearLocation end)
{
ICoordinateList coordinates = line.Coordinates;
CoordinateCollection newCoordinates = new CoordinateCollection();
int startSegmentIndex = start.SegmentIndex;
if (start.SegmentFraction > 0.0)
{
startSegmentIndex += 1;
}
int lastSegmentIndex = end.SegmentIndex;
if (end.SegmentFraction == 1.0)
{
lastSegmentIndex += 1;
}
if (lastSegmentIndex >= coordinates.Count)
{
lastSegmentIndex = coordinates.Count - 1;
}
// not needed - LinearLocation values should always be correct
//Assert.isTrue(end.getSegmentFraction() <= 1.0, "invalid segment fraction value");
if (!start.Vertex)
{
newCoordinates.Add(start.GetCoordinate(line));
}
for (int i = startSegmentIndex; i <= lastSegmentIndex; i++)
{
newCoordinates.Add(coordinates[i]);
}
if (!end.Vertex)
{
newCoordinates.Add(end.GetCoordinate(line));
}
// ensure there is at least one coordinate in the result
if (newCoordinates.Count <= 0)
{
newCoordinates.Add(start.GetCoordinate(line));
}
Coordinate[] newCoordinateArray = newCoordinates.ToArray();
// Ensure there is enough coordinates to build a valid line.
// Make a 2-point line with duplicate coordinates, if necessary.
// There will always be at least one coordinate in the coordList.
if (newCoordinateArray.Length <= 1)
{
newCoordinateArray = new Coordinate[] { newCoordinateArray[0],
newCoordinateArray[0] };
}
return(line.Factory.CreateLineString(newCoordinateArray));
}
private static int SegmentEndVertexIndex(LinearLocation loc)
{
if (loc.SegmentFraction > 0.0)
{
return(loc.SegmentIndex + 1);
}
return(loc.SegmentIndex);
}
/// <summary>
/// Computes the <see cref="LineString"/> for the interval on the line
/// between the given indices.
/// </summary>
/// <param name="startIndex">
/// The index of the start of the interval.
/// </param>
/// <param name="endIndex">
/// The index of the end of the interval.
/// </param>
/// <returns>The linear interval between the indices.</returns>
/// <remarks>
/// If the endIndex lies before the startIndex, the computed
/// geometry is reversed.
/// </remarks>
public virtual Geometry ExtractLine(double startIndex, double endIndex)
{
// LocationIndexedLine lil = new LocationIndexedLine(linearGeom);
LinearLocation startLoc = LocationOf(startIndex);
LinearLocation endLoc = LocationOf(endIndex);
return(ExtractLineByLocation.Extract(linearGeom,
startLoc, endLoc));
}
private LinearLocation IndexOfFromStart(Coordinate inputPt,
LinearLocation minIndex)
{
double minDistance = Double.MaxValue;
int minComponentIndex = 0;
int minSegmentIndex = 0;
double minFrac = -1.0;
LineSegment seg = new LineSegment(linearGeom.Factory);
for (LinearIterator it = new LinearIterator(linearGeom);
it.HasNext(); it.Next())
{
if (!it.EndOfLine)
{
seg.p0 = it.SegmentStart;
seg.p1 = it.SegmentEnd;
double segDistance = seg.Distance(inputPt);
double segFrac = SegmentFraction(seg, inputPt);
int candidateComponentIndex = it.ComponentIndex;
int candidateSegmentIndex = it.VertexIndex;
if (segDistance < minDistance)
{
// ensure after minLocation, if any
if (minIndex == null || minIndex.CompareLocationValues(
candidateComponentIndex, candidateSegmentIndex,
segFrac) < 0)
{
// otherwise, save this as new minimum
minComponentIndex = candidateComponentIndex;
minSegmentIndex = candidateSegmentIndex;
minFrac = segFrac;
minDistance = segDistance;
}
}
}
}
LinearLocation loc = new LinearLocation(minComponentIndex,
minSegmentIndex, minFrac);
return(loc);
}
private LinearLocation GetLocationForward(double length)
{
if (length <= 0.0)
{
return(new LinearLocation());
}
double totalLength = 0.0;
LinearIterator it = new LinearIterator(linearGeom);
while (it.HasNext())
{
if (!it.EndOfLine)
{
Coordinate p0 = it.SegmentStart;
Coordinate p1 = it.SegmentEnd;
double segLen = p1.Distance(p0);
// length falls in this segment
if ((totalLength + segLen) > length)
{
double frac = (length - totalLength) / segLen;
int compIndex = it.ComponentIndex;
int segIndex = it.VertexIndex;
return(new LinearLocation(compIndex, segIndex, frac));
}
totalLength += segLen;
}
it.Next();
}
// length is longer than line - return end location
return(LinearLocation.GetEndLocation(linearGeom));
}
/// <summary>
/// Computes the length for a given <see cref="LinearLocation"/>
/// on a linear <see cref="Geometry"/>.
/// </summary>
/// <param name="line">The linear geometry to use.</param>
/// <param name="loc">
/// The <see cref="LinearLocation"/> index of the location.
/// </param>
/// <returns>
/// This returns the length for the <see cref="LinearLocation"/>.
/// </returns>
public static double GetLength(Geometry linearGeom, LinearLocation loc)
{
LengthLocationMap locater = new LengthLocationMap(linearGeom);
return(locater.GetLength(loc));
}
/// <summary>
/// Creates an iterator starting at a <see cref="LinearLocation"/> on
/// a linear <see cref="Geometry"/>.
/// </summary>
/// <param name="linear">The linear geometry to iterate over.</param>
/// <param name="start">The location to start at.</param>
public LinearIterator(Geometry linear, LinearLocation start)
: this(linear, start.ComponentIndex, SegmentEndVertexIndex(start))
{
}
/// <summary> Tests whether an index is in the valid index range for the line.
///
/// </summary>
/// <param name="length">the index to test
/// </param>
/// <returns> <see langword="true"/> if the index is in the valid range
/// </returns>
public bool IsValidIndex(LinearLocation index)
{
return(index.IsValid(linearGeom));
}
/// <summary> Computes the <see cref="LineString"/> for the interval
/// on the line between the given indices.
///
/// </summary>
/// <param name="startIndex">the index of the start of the interval
/// </param>
/// <param name="endIndex">the index of the end of the interval
/// </param>
/// <returns> the linear interval between the indices
/// </returns>
public Geometry ExtractLine(LinearLocation startIndex,
LinearLocation endIndex)
{
return(ExtractLineByLocation.Extract(linearGeom,
startIndex, endIndex));
}
/// <summary> Computes the <see cref="Coordinate"/> for the point
/// on the line at the given index.
/// If the index is out of range the first or last point on the
/// line will be returned.
///
/// </summary>
/// <param name="length">the index of the desired point
/// </param>
/// <returns> the Coordinate at the given index
/// </returns>
public Coordinate ExtractPoint(LinearLocation index)
{
return(index.GetCoordinate(linearGeom));
}