This is an intergradation of edges from spatial data to graph data, and each edge cooresponds to one row in the object, of which the row structure is designed as [EdgeID,NodeID(from),NodeID(to)].
This object is the immediate result of establishing edges between nodes from a “SpatialLines” or “SpatialLinesDataFrame” object, see readshpnw. As a transition object, it is a necessary input for many functions in this package.