The purpose of a transportation network it to link locations and thus confer a level of spatial continuity. Networks A and B are servicing the same territory, but both have a level of discontinuity (especially network A). If a transfer between those two networks is possible then their combination (network C) increases the level of spatial continuity. If networks A and B concern different modes, then the spatial continuity is provided by intermodal nodes (nodes between modes). If networks A and B involve the same mode, then the spatial continuity is provided by transmodal nodes (nodes within the same mode).