/// <summary>
///
/// </summary>
/// <param name="loc"></param>
/// <returns></returns>
public double GetLength(LinearLocation loc)
{
double totalLength = 0.0;
foreach (LinearIterator.LinearElement element in new LinearIterator(linearGeom))
{
if (!element.IsEndOfLine)
{
ICoordinate p0 = element.SegmentStart;
ICoordinate p1 = element.SegmentEnd;
double segLen = p1.Distance(p0);
// length falls in this segment
if (loc.ComponentIndex == element.ComponentIndex && loc.SegmentIndex == element.VertexIndex)
{
return(totalLength + segLen * loc.SegmentFraction);
}
totalLength += segLen;
}
}
return(totalLength);
}
/// <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>
///
/// </summary>
/// <param name="subLine"></param>
/// <returns></returns>
public virtual LinearLocation[] IndicesOf(IGeometry subLine)
{
ICoordinate startPt = ((ILineString)subLine.GetGeometryN(0)).GetCoordinateN(0);
ILineString lastLine = (ILineString)subLine.GetGeometryN(subLine.NumGeometries - 1);
ICoordinate endPt = lastLine.GetCoordinateN(lastLine.NumPoints - 1);
LocationIndexOfPoint locPt = new LocationIndexOfPoint(linearGeom);
LinearLocation[] subLineLoc = new LinearLocation[2];
subLineLoc[0] = locPt.IndexOf(startPt);
// check for case where subline is zero length
if (subLine.Length == 0)
{
subLineLoc[1] = (LinearLocation)subLineLoc[0].Clone();
}
else
{
subLineLoc[1] = locPt.IndexOfAfter(endPt, subLineLoc[0]);
}
return(subLineLoc);
}
/// <summary>
/// Find the nearest <see cref="LinearLocation" /> along the linear <see cref="Geometry" />
/// to a given <see cref="Geometry" /> after the specified minimum <see cref="LinearLocation" />.
/// If possible the location returned will be strictly greater than the <paramref name="minIndex" />.
/// If this is not possible, the value returned will equal <paramref name="minIndex" />.
/// (An example where this is not possible is when <paramref name="minIndex" /> = [end of line] ).
/// </summary>
/// <param name="inputPt">The coordinate to locate.</param>
/// <param name="minIndex">The minimum location for the point location.</param>
/// <returns>The location of the nearest point.</returns>
public LinearLocation IndexOfAfter(ICoordinate inputPt, LinearLocation minIndex)
{
if (minIndex == null)
{
return(IndexOf(inputPt));
}
// sanity check for minLocation at or past end of line
LinearLocation endLoc = LinearLocation.GetEndLocation(linearGeom);
if (endLoc.CompareTo(minIndex) <= 0)
{
return(endLoc);
}
LinearLocation closestAfter = IndexOfFromStart(inputPt, minIndex);
/*
* Return the minDistanceLocation found.
* This will not be null, since it was initialized to minLocation
*/
Assert.IsTrue(closestAfter.CompareTo(minIndex) >= 0, "computed location is before specified minimum location");
return(closestAfter);
}
/// <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());
}
/// <summary>
/// Computes the subline of a <see cref="LineString" /> between
/// two LineStringLocations on the line.
/// If the start location is after the end location,
/// the computed geometry is reversed.
/// </summary>
/// <param name="line">The line to use as the baseline.</param>
/// <param name="start">The start location.</param>
/// <param name="end">The end location.</param>
/// <returns>The extracted subline.</returns>
public static IGeometry Extract(IGeometry line, LinearLocation start, LinearLocation end)
{
ExtractLineByLocation ls = new ExtractLineByLocation(line);
return(ls.Extract(start, end));
}
/// <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(IGeometry linear, LinearLocation start) :
this(linear, start.ComponentIndex, SegmentEndVertexIndex(start))
{
}
/// <summary>
/// Computes the length for a given <see cref="LinearLocation" />
/// on a linear <see cref="Geometry" />.
/// </summary>
/// <param name="linearGeom">The linear geometry to use.</param>
/// <param name="loc">The <see cref="LinearLocation" /> index of the location.</param>
/// <returns>The length for the <see cref="LinearLocation" />.</returns>
public static double GetLength(IGeometry linearGeom, LinearLocation loc)
{
LengthLocationMap locater = new LengthLocationMap(linearGeom);
return(locater.GetLength(loc));
}
/// <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="index">The index of the desired point.</param>
/// <returns>The <see cref="Coordinate" /> at the given index.</returns>
public ICoordinate ExtractPoint(double index)
{
LinearLocation loc = LengthLocationMap.GetLocation(linearGeom, index);
return(loc.GetCoordinate(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 IGeometry 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 <paramref name="index" /> is out of range,
/// the first or last point on the line will be returned.
/// </summary>
/// <param name="index">The index of the desired point.</param>
/// <returns>The <see cref="Coordinate" /> at the given index.</returns>
public ICoordinate ExtractPoint(LinearLocation index)
{
return(index.GetCoordinate(linearGeom));
}
/// <summary>
/// Tests whether an index is in the valid index range for the line.
/// </summary>
/// <param name="index">The index to test.</param>
/// <returns><c>true</c> if the index is in the valid range.</returns>
public bool isValidIndex(LinearLocation index)
{
return(index.IsValid(linearGeom));
}