We’ve all been there. It’s crunch time and you encounter hundreds or maybe thousands of individual line segments that should be continuous polylines. The end points are snapped together, but when you try to select them or perform some analysis on them, you get individual lines, or lots of unconnected polylines.
There is a much better, though often overlooked alternative to the Polyline Edit > Join command, in the Drawing Cleanup suite of tools, called Dissolve Pseudo Nodes.
For the complete tutorial, (and many others) follow this link...