/// <summary>
///
/// </summary>
/// <param name="inputPt"></param>
/// <param name="minIndex"></param>
/// <returns></returns>
private LinearLocation IndexOfFromStart(ICoordinate inputPt, LinearLocation minIndex)
{
double minDistance = Double.MaxValue;
int minComponentIndex = 0;
int minSegmentIndex = 0;
double minFrac = -1.0;
LineSegment seg = new LineSegment();
foreach (LinearIterator.LinearElement element in new LinearIterator(linearGeom))
{
if (!element.IsEndOfLine)
{
seg.P0 = element.SegmentStart;
seg.P1 = element.SegmentEnd;
double segDistance = seg.Distance(inputPt);
double segFrac = SegmentFraction(seg, inputPt);
int candidateComponentIndex = element.ComponentIndex;
int candidateSegmentIndex = element.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);
}
/// <summary>
/// Assumes input is valid
/// (e.g. <paramref name="start" /> minor or equals to <paramref name="end" />).
/// </summary>
/// <param name="start"></param>
/// <param name="end"></param>
/// <returns></returns>
private IGeometry ComputeLinear(LinearLocation start, LinearLocation end)
{
LinearGeometryBuilder builder = new LinearGeometryBuilder(line.Factory);
builder.FixInvalidLines = true;
if (!start.IsVertex)
{
builder.Add(start.GetCoordinate(line));
}
LinearIterator it = new LinearIterator(line, start);
foreach (LinearIterator.LinearElement element in it)
{
int compare = end.CompareLocationValues(element.ComponentIndex, element.VertexIndex, 0.0);
if (compare < 0)
{
break;
}
ICoordinate pt = element.SegmentStart;
builder.Add(pt);
if (element.IsEndOfLine)
{
builder.EndLine();
}
}
if (!end.IsVertex)
{
builder.Add(end.GetCoordinate(line));
}
return(builder.GetGeometry());
}