private double ComputeDistancePointLine(Coordinate pt, FacetSequence facetSeq, GeometryLocation[] locs)
{
double minDistance = double.MaxValue;
for (int i = facetSeq._start; i < facetSeq._end - 1; i++)
{
var q0 = facetSeq._pts.GetCoordinate(i);
var q1 = facetSeq._pts.GetCoordinate(i + 1);
double dist = DistanceComputer.PointToSegment(pt, q0, q1);
if (dist < minDistance)
{
minDistance = dist;
if (locs != null)
{
UpdateNearestLocationsPointLine(pt, facetSeq, i, q0, q1, locs);
}
if (minDistance <= 0)
{
return(minDistance);
}
}
}
return(minDistance);
}
private double ComputeDistanceLineLine(FacetSequence facetSeq, GeometryLocation[] locs)
{
// both linear - compute minimum segment-segment distance
double minDistance = double.MaxValue;
for (int i = _start; i < _end - 1; i++)
{
var p0 = _pts.GetCoordinate(i);
var p1 = _pts.GetCoordinate(i + 1);
for (int j = facetSeq._start; j < facetSeq._end - 1; j++)
{
var q0 = facetSeq._pts.GetCoordinate(j);
var q1 = facetSeq._pts.GetCoordinate(j + 1);
double dist = DistanceComputer.SegmentToSegment(p0, p1, q0, q1);
if (dist < minDistance)
{
minDistance = dist;
if (locs != null)
{
UpdateNearestLocationsLineLine(i, p0, p1, facetSeq, j, q0, q1, locs);
}
if (minDistance <= 0)
{
return(minDistance);
}
}
}
}
return(minDistance);
}
/// <summary>
/// Computes the distance between this and another
/// <see cref="FacetSequence"/>.
/// </summary>
/// <param name="facetSeq">The sequence to compute the distance to.</param>
/// <returns>The minimum distance between the sequences.</returns>
public double Distance(FacetSequence facetSeq)
{
bool isPoint = IsPoint;
bool isPointOther = facetSeq.IsPoint;
double distance;
if (isPoint && isPointOther)
{
var pt = _pts.GetCoordinate(_start);
var seqPt = facetSeq._pts.GetCoordinate(facetSeq._start);
distance = pt.Distance(seqPt);
}
else if (isPoint)
{
var pt = _pts.GetCoordinate(_start);
distance = ComputeDistancePointLine(pt, facetSeq, null);
}
else if (isPointOther)
{
var seqPt = facetSeq._pts.GetCoordinate(facetSeq._start);
distance = ComputeDistancePointLine(seqPt, this, null);
}
else
{
distance = ComputeDistanceLineLine(facetSeq, null);
}
return(distance);
}
private void UpdateNearestLocationsPointLine(Coordinate pt,
FacetSequence facetSeq, int i, Coordinate q0, Coordinate q1,
GeometryLocation[] locs)
{
locs[0] = new GeometryLocation(_geom, _start, pt.Copy());
var seg = new LineSegment(q0, q1);
var segClosestPoint = seg.ClosestPoint(pt);
locs[1] = new GeometryLocation(facetSeq._geom, i, segClosestPoint.Copy());
}
private static void AddFacetSequences(Geometry geom, CoordinateSequence pts, List <FacetSequence> sections)
{
int i = 0;
int size = pts.Count;
while (i <= size - 1)
{
int end = i + FacetSequenceSize + 1;
// if only one point remains after this section, include it in this
// section
if (end >= size - 1)
{
end = size;
}
var sect = new FacetSequence(geom, pts, i, end);
sections.Add(sect);
i = i + FacetSequenceSize;
}
}
/// <summary>
/// Computes the locations of the nearest points between this sequence
/// and another sequence.
/// The locations are presented in the same order as the input sequences.
/// </summary>
/// <returns>A pair of <see cref="GeometryLocation"/>s for the nearest points.</returns>
public GeometryLocation[] NearestLocations(FacetSequence facetSeq)
{
bool isPoint = IsPoint;
bool isPointOther = facetSeq.IsPoint;
var locs = new GeometryLocation[2];
if (isPoint && isPointOther)
{
// DEVIATION (minor): JTS uses "new Coordinate(GetCoordinate(int))", which is worse
// than "GetCoordinateCopy(int)" for two reasons: 1) doesn't copy M (or, in NTS, Z),
// and 2) might allocate two Coordinate instances instead of one.
var pt = _pts.GetCoordinateCopy(_start);
var seqPt = facetSeq._pts.GetCoordinateCopy(facetSeq._start);
locs[0] = new GeometryLocation(_geom, _start, pt);
locs[1] = new GeometryLocation(facetSeq._geom, facetSeq._start, seqPt);
}
else if (isPoint)
{
var pt = _pts.GetCoordinateCopy(_start);
ComputeDistancePointLine(pt, facetSeq, locs);
}
else if (isPointOther)
{
var seqPt = facetSeq._pts.GetCoordinateCopy(facetSeq._start);
ComputeDistancePointLine(seqPt, this, locs);
// unflip the locations
(locs[0], locs[1]) = (locs[1], locs[0]);
}
else
{
ComputeDistanceLineLine(facetSeq, locs);
}
return(locs);
}
private void UpdateNearestLocationsLineLine(int i, Coordinate p0, Coordinate p1, FacetSequence facetSeq, int j,
Coordinate q0, Coordinate q1, GeometryLocation[] locs)
{
var seg0 = new LineSegment(p0, p1);
var seg1 = new LineSegment(q0, q1);
var closestPt = seg0.ClosestPoints(seg1);
locs[0] = new GeometryLocation(_geom, i, closestPt[0].Copy());
locs[1] = new GeometryLocation(facetSeq._geom, j, closestPt[1].Copy());
}