Does a cell boundary associate to only one cell space?

[kijouneli]

Figure 16 shows the association between CellSpace and CellBoundary as below;

It means that a cell boundary shall be associated with only ONE cell space. Does it mean that when CB1 (a cell boundary) bounds C1 (a cell), we need to add an additional cell boundary (e.g. CB2) for C2 as well?

[abdoulayediak]

The idea is that a CellBoundary is associated to only one CellSpace. So a CB2 is needed for C2, and CB1 and CB2 can have the same geometry but will have different orientation.

However, this brings another problem in the dual space because. In the network N1---(E1)---N2, to which CellBoundary E1 is associated with, CB1 or CB2? I don't see a quick fix yet bit this is related to issue #3 in the sense that it holds to the cardinality between CellBoundary and Edge.

[kunlinyu]

This is my implementation.
CellBoundary has one "leftSpace" and one "rightSpace".
The type of them is "CellSpace?", "?" means it is nullable.

using NetTopologySuite.Geometries;

public class CellBoundary
{
    CellVertex P0 { get; private set; }
    CellVertex P1 { get; private set; }

    LineString geometry;

    CellSpace? leftSpace;
    CellSpace? rightSpace;

    Navigable navigable { set; get; } = Navigable.Navigable;

    NaviDirection naviDir { set; get; } = NaviDirection.Left2Right;

    public CellBoundary(Coordinate p0, Coordinate p1)
    {
        P0 = new CellVertex(p0);
        P1 = new CellVertex(p1);
        geometry = new GeometryFactory().CreateLineString(new Coordinate[] { P0.Coordinate, P1.Coordinate });
    }
}

public enum Navigable
{
    PhysicallyNonNavigable = 0,
    LogicallyNonNavigable = 1,
    Navigable = 2,
    Mix = 3,
}

public enum NaviDirection
{
    NoneDirection,
    Left2Right,
    Right2Left,
    BiDirection,
}

This implementation of CellBoundary is a hyper-concept of CellBoundary in IndoorGML.
No matter how we define CellBoundary in IndoorGML, my code can generate the correct XML file.

My point is, in current standard, if CellBoundary is associated to only one CellSpace, then CellBoundary is a low level data structure. But what we really need is a high level data structure.
The high level CellBoundary know how many CellSpaces are partial bounded by itself.
It may generate low level CellBoundary.
It can record the navigable and navigation direction and so on.
And, the high level CellBoundary is the duality of edge. Low level CellBoundary is not the duality of edge.

[kijouneli]

@kunlinyu, It looks interesting to distinguish low level and high level CellBoundary.
@abdoulayediak, yes. it is true that this is related with issue #3 as well as #7 (directed vs. undirected) because two CellBoundary's may associated to edges and consequently to two directions.