To trace upstream:

1. Click on the Trace mode control and select Trace Upstream.

   

2. Click on the Select "From" Feature button. The command prompt reads: From: > Identify element.

   

3. Click on a gas feature in the graphical view to identify the start feature for the Trace. The feature label appears in the "From" Feature display.

   

4. Press on the Trace button. Features connected upstream from the start feature are highlighted.