Set the flow direction

The direction of flow in a trace network is determined by the value set in the FLOWDIRECTION field. When a trace network is created or converted from a geometric network, the Flow direction network attribute is created on all line feature classes that participate in the network.

Note:

Trace Network Version 1 requires the use of the Set Flow Direction tool to update the flow direction of line features in the network. The trace network can be upgraded to Trace Network Version 2 or later to use the Flow direction network attribute and associated workflows. See Trace network upgrade history for more information.

By default, flow is established with the digitized direction of a network edge. A coded-value domain is used to set the direction of flow in three ways:

• Indeterminate direction—Flow direction is bidirectional or undetermined.
• With digitized direction—Flow direction is established along the digitized direction of edges. This is the default.
• Against digitized direction—Flow direction is established against the digitized direction of edges.

To set flow direction on line features in a trace network, complete the following steps:

1. On the Edit tab, in the Selection group, click Attributes .
2. Click Select , select the features, and expand the selection in the pane.
   • To select multiple features and edit the same field with the same value, use the following keyboard shortcuts:
     • To select multiple features, press Ctrl while clicking the features.
     • To select adjacent features, press Shift while clicking the first and last feature.
3. Click the cell to the right of Flow direction to choose the value from the available options in the domain and press Enter.
4. If Auto Apply is turned off, click Apply.
   • The FLOWDIRECTION field can also be edited in the attribute table manually or by using the Calculate Field tool.

   When an edit is made to a network attribute, a dirty area is generated to mark the feature for validation. Validation ensures that the flow direction is updated in network topology.

5. To validate the edits and update the network topology, under Trace Network, click the Data tab.
6. In the Network Topology group, click the Validate command.
   • Depending on the scope of edits made, you can choose to validate the Current Extent or Entire Extent. See Validate a network topology for more information.

The flow direction is updated for the selected features. Under Trace Network, on the Data tab in the Flow Direction group, use the Display Flow Direction command to create a flow direction layer for visualization.