Joining double connections
Joins edges between same nodes using NBNodeCont::recheckEdges().
Finding isolated roads (optional)
Removing empty nodes and geometry nodes (optional)
Removed nodes with no incoming/outgoing edges and nodes which can be transformed into geometry point using NBNodeCont::removeUnwishedNodes().
Removing unwished edges (optional)
If "keep-edges.postload" and "keep-edges.explicit" are set, the edges not within "keep-edges.explicit" are removed from the network using NBEdgeCont::removeUnwishedEdges().
Rechecking nodes after edge removal (optional)
If any of the edge removing options was set ("keep-edges.explicit", "remove-edges.explicit", "keep-edges.postload", "keep-edges.by-vclass", "keep-edges.input-file"), the now orphaned nodes are removed using NBNodeCont::removeUnwishedNodes().
Splitting geometry edges (optional)
If "geometry.split" is set, edge geometries are converted to nodes using NBEdgeCont::splitGeometry().
Normalising/transposing node positions
If "offset.disable-normalization", "offset.x", and "offset.y" are not set, the road graph's instances are moved to the origin.