What was the purpose of inserting centerlines through water bodies and wide rivers?
Centerlines were added o provide single-line transport paths thru water body features. All but just a few PNW reach files contained areal features such as lakes, ponds, reservoirs, or open bodies of water at the mouths of large rivers or around the Puget Sound, or wide rivers with left and right banks. These features were extracted out of each reach file and put in a seperate coverage we named Banks-pnw. We replaced the areal features with centerlines and connector segments from the centerline to any tributary. By modifying the reachfile in such a manner it created not only a hydrologically ordered stream network but also allowed tabular users to migrate the network in both directions and not be concerned that they may have traversed one side of a waterbody going one way and then jumped to the opposite side going the other. If such a situation did occur it would be impossible to tell in a tabular file if and where tributaries entered the waterbody. Centerlining was important for non-GI
