The output from the GeoProcessing wizard Dissolve tool may include line segments that flow in a direction opposite to the original line segments.
The line directions of the input features are being ignored as the dissolve function creates new features. These new features have line directions independent of the line direction of the original input features.
Solution or Workaround
This issue has been addressed in ArcGIS Version 8.1.2.
In ArcGIS 8.1, change the direction of a line segment by editing the dissolve output.
- Click Editor on the Edit toolbar and select Start Editing.
- Double-click the line segment whose direction you want to change.
- Right-click and select Flip.
Repeat this for all line segments you want to change and then save your edits and finish the edit session.