Link

A Link is a topological LineString item that stores data regarding its topological relationship with other topological items.

A Link item is a sub-class of a LineString item that is created using Link (Topology > Build). A Link item has a Node item at each end.

Link items are also used to define the geometry of TopoLineString and TopoPolygon items, and can be created as a side-effect of creating TopoPolygon items.

Properties

• Automatic: _bAuto&
  Was the Node item automatically created? Automatic Node items may be automatically deleted in future when associated Link items are edited or deleted.
  
  
• Closed: _closed&
  Does the geometry of the item form a closed loop?
  
  
• Direction flags: _fDirection&
  The restrictions on flow direction of a Link item. This affects the route finding algorithm. By default a Link item can be followed by the route finding algorithm in both directions.
  0 (Both) = Two way, i.e. there are no direction restrictions.
  1 (In) = One way, i.e. from start to end mode.
  2 (Out) = Other way, i.e. reverse direction to "1 (In)" above.
  3 (None) = Neither direction allowed, i.e. link cannot be routed along, it is closed.
  
  
• End node: _id2&
  The ID of the Node item at the end of the Link item.
  
  
• Geometry class: _classGeom$
  The C++ class used to store an item's geometry. This is handled automatically. You can see what precision an item's geometry is stored with by recognising the geometry classes.
  
  
• Number of coverages: _nCoverage&
  The number of "coverages" in which a Link is used.
  
  
• Number of seeds: _nSeed&
  The number of TopoPolygon or TopoLineString items of which this Link item forms part.
  
  
• Number of vertices: _np&
  The number of vertices in the item's geometry.
  
  
• Seeds: _seeds$
  The topological TopoLineString and TopoPolygon items which a Link item forms part of.
  
  
• Start node: _id1&
  The ID of the Node item at the start of the Link item.
  

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