/// <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(CP0, cP1, new Coordinate(line.P0), new Coordinate(line.P1));
if (li.HasIntersection)
return li.GetIntersection(0);
return null;
}
/// <summary>
/// Checks validity of a LinearRing.
/// </summary>
/// <param name="g"></param>
private void CheckValidRing(ILinearRing g)
{
CheckClosedRing(g);
if (_validErr != null) return;
GeometryGraph graph = new GeometryGraph(0, g);
LineIntersector li = new RobustLineIntersector();
graph.ComputeSelfNodes(li, true);
CheckNoSelfIntersectingRings(graph);
}
/// <summary>
///
/// </summary>
/// <param name="geom"></param>
/// <returns></returns>
private bool IsSimpleLinearGeometry(Geometry geom)
{
if (geom.IsEmpty)
return true;
GeometryGraph graph = new GeometryGraph(0, geom);
LineIntersector li = new RobustLineIntersector();
SegmentIntersector si = graph.ComputeSelfNodes(li, true);
// if no self-intersection, must be simple
if (!si.HasIntersection) return true;
if (si.HasProperIntersection) return false;
if (HasNonEndpointIntersection(graph)) return false;
if (HasClosedEndpointIntersection(graph)) return false;
return true;
}
/// <summary>
/// Test whether a point lies on the line segments defined by a
/// list of coordinates.
/// </summary>
/// <param name="p"></param>
/// <param name="pt"></param>
/// <returns>
/// <c>true</c> true if
/// the point is a vertex of the line or lies in the interior of a line
/// segment in the linestring.
/// </returns>
public static bool IsOnLine(Coordinate p, IList<Coordinate> pt)
{
LineIntersector lineIntersector = new RobustLineIntersector();
for (int i = 1; i < pt.Count; i++)
{
Coordinate p0 = pt[i - 1];
Coordinate p1 = pt[i];
lineIntersector.ComputeIntersection(p, p0, p1);
if (lineIntersector.HasIntersection)
return true;
}
return false;
}
/// <summary>
///
/// </summary>
/// <param name="precisionModel"></param>
/// <returns></returns>
private INoder GetNoder(PrecisionModel precisionModel)
{
if (workingNoder != null)
return workingNoder;
// otherwise use a fast (but non-robust) noder
LineIntersector li = new RobustLineIntersector();
li.PrecisionModel = precisionModel;
MCIndexNoder noder = new MCIndexNoder(new IntersectionAdder(li));
return noder;
}
