public double GetLength(LinearLocation loc)
{
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 (loc.ComponentIndex == it.ComponentIndex &&
loc.SegmentIndex == it.VertexIndex)
{
return(totalLength + segLen * loc.SegmentFraction);
}
totalLength += segLen;
}
it.Next();
}
return(totalLength);
}
private double IndexOfFromStart(Coordinate inputPt, double minIndex)
{
double minDistance = Double.MaxValue;
double ptMeasure = minIndex;
double segmentStartMeasure = 0.0;
LineSegment seg = new LineSegment(linearGeom.Factory);
LinearIterator it = new LinearIterator(linearGeom);
while (it.HasNext())
{
if (!it.EndOfLine)
{
seg.p0 = it.SegmentStart;
seg.p1 = it.SegmentEnd;
double segDistance = seg.Distance(inputPt);
double segMeasureToPt = SegmentNearestMeasure(seg,
inputPt, segmentStartMeasure);
if (segDistance < minDistance && segMeasureToPt > minIndex)
{
ptMeasure = segMeasureToPt;
minDistance = segDistance;
}
segmentStartMeasure += seg.Length;
}
it.Next();
}
return(ptMeasure);
}
/// <summary>
/// Assumes input is valid (e.g. start <= end)
/// </summary>
/// <param name="start">
/// </param>
/// <param name="end">
/// </param>
/// <returns> a linear geometry
/// </returns>
private Geometry ComputeLinear(LinearLocation start, LinearLocation end)
{
LinearGeometryBuilder builder = new LinearGeometryBuilder(line.Factory);
builder.FixInvalidLines = true;
if (!start.Vertex)
{
builder.Add(start.GetCoordinate(line));
}
for (LinearIterator it = new LinearIterator(line, start);
it.HasNext(); it.Next())
{
if (end.CompareLocationValues(it.ComponentIndex,
it.VertexIndex, 0.0) < 0)
{
break;
}
Coordinate pt = it.SegmentStart;
builder.Add(pt);
if (it.EndOfLine)
{
builder.EndLine();
}
}
if (!end.Vertex)
{
builder.Add(end.GetCoordinate(line));
}
return(builder.Geometry);
}
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));
}
