Median Offset
This command creates a median polyline that is offset halfway
between two existing polylines. For example, this command can be
used to get the center of a river given polylines for the left and
right river banks.
Prompts
Select the First Polyline: pick a polyline
Select the Second Polyline: pick a polyline
Which type of solution method [Salient/<Normal>]?
press Enter
Draw Chords of Parabolas [Yes/<No>]? press
Enter
Draw Perpendiculars for Check [<Yes>/No]? press
Enter
Pulldown Menu Location: Edit > Offset
Keyboard Command: medoff
Prerequisite: two polylines to offset