public static Geometry SegmentIntersection(Geometry g1, Geometry g2)
{
var pt1 = g1.Coordinates;
var pt2 = g2.Coordinates;
var ri = new RobustLineIntersector();
ri.ComputeIntersection(pt1[0], pt1[1], pt2[0], pt2[1]);
switch (ri.IntersectionNum)
{
case 0:
// no intersection => return empty point
return(g1.Factory.CreatePoint((Coordinate)null));
case 1:
// return point
return(g1.Factory.CreatePoint(ri.GetIntersection(0)));
case 2:
// return line
return(g1.Factory.CreateLineString(
new Coordinate[] {
ri.GetIntersection(0),
ri.GetIntersection(1)
}));
}
return(null);
}
public void TestEndpointIntersection2()
{
i.ComputeIntersection(new Coordinate(190, 50), new Coordinate(120, 100),
new Coordinate(120, 100), new Coordinate(50, 150));
Assert.IsTrue(i.HasIntersection);
Assert.AreEqual(1, i.IntersectionNum);
Assert.AreEqual(new Coordinate(120, 100), i.GetIntersection(1));
}
/// <summary>
/// Computes an intersection point between two segments, if there is one.
/// There may be 0, 1 or many intersection points between two segments.
/// If there are 0, null is returned. If there is 1 or more, a single one
/// is returned (chosen at the discretion of the algorithm). If
/// more information is required about the details of the intersection,
/// the {RobustLineIntersector} class should be used.
/// </summary>
/// <param name="line"></param>
/// <returns> An intersection point, or <c>null</c> if there is none.</returns>
public virtual Coordinate Intersection(ILineSegmentBase line)
{
LineIntersector li = new RobustLineIntersector();
li.ComputeIntersection(P0, P1, new Coordinate(line.P0), new Coordinate(line.P1));
if (li.HasIntersection)
{
return(li.GetIntersection(0));
}
return(null);
}
/// <summary>
/// Computes an intersection point between two segments, if there is one.
/// There may be 0, 1 or many intersection points between two segments.
/// If there are 0, null is returned. If there is 1 or more, a single one
/// is returned (chosen at the discretion of the algorithm). If
/// more information is required about the details of the intersection,
/// the {RobustLineIntersector} class should be used.
/// </summary>
/// <param name="line">A line segment</param>
/// <returns> An intersection point, or <c>null</c> if there is none.</returns>
/// <see cref="RobustLineIntersector"/>
public Coordinate Intersection(LineSegment line)
{
LineIntersector li = new RobustLineIntersector();
li.ComputeIntersection(_p0, _p1, line._p0, line._p1);
if (li.HasIntersection)
{
return(li.GetIntersection(0));
}
return(null);
}
private void CheckIntersectionDir(LineSegment line1, LineSegment line2, Coordinate pt)
{
LineIntersector li = new RobustLineIntersector();
li.ComputeIntersection(
line1.P0, line1.P1,
line2.P0, line2.P1);
Assert.That(li.IntersectionNum, Is.EqualTo(1));
var actual = li.GetIntersection(0);
CheckEqualXYZ(pt, actual);
}
private void CheckIntersectionDir(LineSegment line1, LineSegment line2, Coordinate p1, Coordinate p2)
{
LineIntersector li = new RobustLineIntersector();
li.ComputeIntersection(
line1.P0, line1.P1,
line2.P0, line2.P1);
Assert.That(li.IntersectionNum, Is.EqualTo(2));
var actual1 = li.GetIntersection(0);
var actual2 = li.GetIntersection(1);
// normalize actual results
if (actual1.CompareTo(actual2) > 0)
{
actual1 = li.GetIntersection(1);
actual2 = li.GetIntersection(0);
}
CheckEqualXYZ(p1, actual1);
CheckEqualXYZ(p2, actual2);
}
public void Test2Lines()
{
var i = new RobustLineIntersector();
var p1 = new Coordinate(10, 10);
var p2 = new Coordinate(20, 20);
var q1 = new Coordinate(20, 10);
var q2 = new Coordinate(10, 20);
var x = new Coordinate(15, 15);
i.ComputeIntersection(p1, p2, q1, q2);
Assert.AreEqual(LineIntersector.PointIntersection, i.IntersectionNum);
Assert.AreEqual(1, i.IntersectionNum);
Assert.AreEqual(x, i.GetIntersection(0));
Assert.IsTrue(i.IsProper);
Assert.IsTrue(i.HasIntersection);
}
public void Test2Lines()
{
RobustLineIntersector i = new RobustLineIntersector();
Coordinate p1 = new Coordinate(10, 10);
Coordinate p2 = new Coordinate(20, 20);
Coordinate q1 = new Coordinate(20, 10);
Coordinate q2 = new Coordinate(10, 20);
Coordinate x = new Coordinate(15, 15);
i.ComputeIntersection(p1, p2, q1, q2);
Assert.AreEqual(RobustLineIntersector.DoIntersect, i.IntersectionNum);
Assert.AreEqual(1, i.IntersectionNum);
Assert.AreEqual(x, i.GetIntersection(0));
Assert.IsTrue(i.IsProper);
Assert.IsTrue(i.HasIntersection);
}
/// <summary>
/// Computes an intersection point between two segments, if there is one.
/// </summary>
/// <param name="">line
/// </param>
/// <returns> an intersection point, or null if there is none
/// </returns>
/// <remarks>
/// There may be 0, 1 or many intersection points between two segments.
/// If there are 0, null is returned. If there is 1 or more, a single one
/// is returned (chosen at the discretion of the algorithm). If
/// more information is required about the details of the intersection,
/// the <see cref="RobustLineIntersector"/> class should be used.
/// </remarks>
public Coordinate Intersection(LineSegment line)
{
if (line == null)
{
throw new ArgumentNullException("line");
}
LineIntersector li = new RobustLineIntersector();
li.ComputeIntersection(p0, p1, line.p0, line.p1);
if (li.HasIntersection)
{
return(li.GetIntersection(0));
}
return(null);
}
/// <summary>
/// Check that intersection of segment defined by points in pt array
/// is equal to the expectedIntPt value (up to the given distanceTolerance)
/// </summary>
/// <param name="pt"></param>
/// <param name="expectedIntersectionNum"></param>
/// <param name="expectedIntPt">the expected intersection points (maybe null if not tested)</param>
/// <param name="distanceTolerance">tolerance to use for equality test</param>
private void CheckIntersection(Coordinate[] pt,
int expectedIntersectionNum,
Coordinate[] expectedIntPt,
double distanceTolerance)
{
LineIntersector li = new RobustLineIntersector();
li.ComputeIntersection(pt[0], pt[1], pt[2], pt[3]);
int intNum = li.IntersectionNum;
Assert.AreEqual(expectedIntersectionNum, intNum, "Number of intersections not as expected");
if (expectedIntPt != null)
{
Assert.AreEqual(intNum, expectedIntPt.Length, "Wrong number of expected int pts provided");
// test that both points are represented here
if (intNum == 1)
{
CheckIntPoints(expectedIntPt[0], li.GetIntersection(0), distanceTolerance);
}
else if (intNum == 2)
{
CheckIntPoints(expectedIntPt[1], li.GetIntersection(0), distanceTolerance);
CheckIntPoints(expectedIntPt[1], li.GetIntersection(0), distanceTolerance);
if (!(Equals(expectedIntPt[0], li.GetIntersection(0), distanceTolerance) ||
Equals(expectedIntPt[0], li.GetIntersection(1), distanceTolerance)))
{
CheckIntPoints(expectedIntPt[0], li.GetIntersection(0), distanceTolerance);
CheckIntPoints(expectedIntPt[0], li.GetIntersection(1), distanceTolerance);
}
else if (!(Equals(expectedIntPt[1], li.GetIntersection(0), distanceTolerance) ||
Equals(expectedIntPt[1], li.GetIntersection(1), distanceTolerance)))
{
CheckIntPoints(expectedIntPt[1], li.GetIntersection(0), distanceTolerance);
CheckIntPoints(expectedIntPt[1], li.GetIntersection(1), distanceTolerance);
}
}
}
}
private void AddIntersections()
{
var seqA = GetVertices(_geomA);
var seqB = GetVertices(_geomB);
// NTS-specific: these arrays were only written to, never read from.
////bool[] isIntersected0 = new bool[seqA.Count - 1];
////bool[] isIntersected1 = new bool[seqB.Count - 1];
bool isCCWA = Orientation.IsCCW(seqA);
bool isCCWB = Orientation.IsCCW(seqB);
// Compute rays for all intersections
var li = new RobustLineIntersector();
for (int i = 0; i < seqA.Count - 1; i++)
{
var a0 = seqA.GetCoordinate(i);
var a1 = seqA.GetCoordinate(i + 1);
if (isCCWA)
{
// flip segment orientation
(a0, a1) = (a1, a0);
}
for (int j = 0; j < seqB.Count - 1; j++)
{
var b0 = seqB.GetCoordinate(j);
var b1 = seqB.GetCoordinate(j + 1);
if (isCCWB)
{
// flip segment orientation
(b0, b1) = (b1, b0);
}
li.ComputeIntersection(a0, a1, b0, b1);
if (li.HasIntersection)
{
// NTS-specific: these arrays were only written to, never read from.
////isIntersected0[i] = true;
////isIntersected1[j] = true;
/*
* With both rings oriented CW (effectively)
* There are two situations for segment intersections:
*
* 1) A entering B, B exiting A => rays are IP-A1:R, IP-B0:L
* 2) A exiting B, B entering A => rays are IP-A0:L, IP-B1:R
* (where :L/R indicates result is to the Left or Right).
*
* Use full edge to compute direction, for accuracy.
*/
var intPt = li.GetIntersection(0);
bool isAenteringB = OrientationIndex.CounterClockwise == Orientation.Index(a0, a1, b1);
if (isAenteringB)
{
_area += EdgeRay.AreaTerm(intPt, a0, a1, true);
_area += EdgeRay.AreaTerm(intPt, b1, b0, false);
}
else
{
_area += EdgeRay.AreaTerm(intPt, a1, a0, false);
_area += EdgeRay.AreaTerm(intPt, b0, b1, true);
}
}
}
}
}