/// <summary>
///
/// </summary>
/// <param name="geom"></param>
public virtual void ComputeLabelling(GeometryGraph[] geom)
{
ComputeEdgeEndLabels();
// Propagate side labels around the edges in the star
// for each parent Geometry
PropagateSideLabels(0);
PropagateSideLabels(1);
/*
* If there are edges that still have null labels for a point
* this must be because there are no area edges for that point incident on this node.
* In this case, to label the edge for that point we must test whether the
* edge is in the interior of the point.
* To do this it suffices to determine whether the node for the edge is in the interior of an area.
* If so, the edge has location Interior for the point.
* In all other cases (e.g. the node is on a line, on a point, or not on the point at all) the edge
* has the location Exterior for the point.
*
* Notice that the edge cannot be on the Boundary of the point, since then
* there would have been a parallel edge from the Geometry at this node also labelled Boundary
* and this edge would have been labelled in the previous step.
*
* This code causes a problem when dimensional collapses are present, since it may try and
* determine the location of a node where a dimensional collapse has occurred.
* The point should be considered to be on the Exterior
* of the polygon, but locate() will return Interior, since it is passed
* the original Geometry, not the collapsed version.
*
* If there are incident edges which are Line edges labelled Boundary,
* then they must be edges resulting from dimensional collapses.
* In this case the other edges can be labelled Exterior for this Geometry.
*
* MD 8/11/01 - NOT True! The collapsed edges may in fact be in the interior of the Geometry,
* which means the other edges should be labelled Interior for this Geometry.
* Not sure how solve this... Possibly labelling needs to be split into several phases:
* area label propagation, symLabel merging, then finally null label resolution.
*/
bool[] hasDimensionalCollapseEdge = { false, false };
for (IEnumerator it = GetEnumerator(); it.MoveNext();)
{
EdgeEnd e = (EdgeEnd)it.Current;
Label label = e.Label;
for (int geomi = 0; geomi < 2; geomi++)
{
if (label.IsLine(geomi) && label.GetLocation(geomi) == LocationType.Boundary)
{
hasDimensionalCollapseEdge[geomi] = true;
}
}
}
for (IEnumerator it = GetEnumerator(); it.MoveNext();)
{
EdgeEnd e = (EdgeEnd)it.Current;
Label label = e.Label;
for (int geomi = 0; geomi < 2; geomi++)
{
if (label.IsAnyNull(geomi))
{
LocationType loc;
if (hasDimensionalCollapseEdge[geomi])
{
loc = LocationType.Exterior;
}
else
{
Coordinate p = e.Coordinate;
loc = GetLocation(geomi, p, geom);
}
label.SetAllLocationsIfNull(geomi, loc);
}
}
}
}
