After you extract features, you can apply ENVI’s automatic post-processing cleanup tool to create intersections between polylines that cross one another and to correct overshooting (dangling) polylines.

1. Select one of the following:
• Make the layer to edit the active layer, then from the Vector Parameters menu bar, select Options > Linear Feature Cleanup.
• Make the layer to edit the active layer, right-click in the display group, and select Linear Feature Cleanup.

• Right-click on the layer to edit in the Vector Parameters dialog, and select Linear Feature Cleanup.

  The Linear Feature Cleanup Parameters dialog appears.

2. The Dangle Length Tolerance (Pixels) default value is 20.00. ENVI removes any dangling polylines shorter than this value during automatic feature cleanup. Change the value if needed.
3. Click OK. ENVI removes any dangling polylines and creates intersections between crossing polylines. When complete, ENVI overlays the modified layer on the original layer (using a different Current Layer color). In the Vector Parameters dialog, ENVI adds the new layer, named original_layername_clean, to the Available Vector Layers list.

If desired, you can close the original layer and/or rename the new layer.