You all had this happen: You build a second factory, and at some point it becomes so large that is touches the first one. Now you cannot connect them since there is no global grid that you could have built on, and all the walkways (almost) touch in different angles (of course).
There could be a tool to snap-connect two walkways with a procedurally generated in-between walkway if they are close to each other and less than 45% in angle difference and close in height.