Set starting points and barriers

Trace operations in the trace network require one or more starting points to define the starting location of a trace. Barriers are an optional component and represent a location in the network beyond which the trace cannot travel. To learn more, see Trace a trace network, Starting points, and Barriers.

In the Trace Locations pane, two commands are available for setting starting points and barriers. You can use the Add features command to manually click network features on your map, or you can use the Add selected button to set preselected network features in your map as starting points. The steps below demonstrate these two commands.

Requirements

The network topology must be enabled.

Set starting points and barriers in the Trace Locations pane

Set starting points and barriers using the Trace Locations pane in one of the following ways:

• Add features by manually selecting them in the map view.
• Add selected features from the map view.

Note:

Edge elements in the trace network support a single starting point and barrier. If more than one starting point and one barrier are specified for a network edge element, only the last starting point and barrier are honored; all others are ignored.

Add features by manually selecting them in the map view

You can manually select network features on your map to set them as starting points or barriers. Follow the steps below if the features you want to set as trace locations are not already selected on the map. This workflow uses the default setting in the Trace Locations pane, with Auto Apply checked.

1. On the Trace Network tab, in the Tools group, click Trace Locations to open the Trace Locations pane.

   You can set the active tab in the pane to be Starting Points or Barriers .

2. In the Trace Locations pane, confirm that the Starting Points or Barriers tab is active.
3. In the Trace Locations pane, confirm that Auto Apply is checked.
4. With the Add features command active, click a network feature on the map.

   You can place a starting point or barrier on any network feature, a point feature, anywhere along a line feature, and on a polygon feature.

   • A green circle appears where you clicked to represent a starting point.
   • A red x appears where you clicked to represent a barrier.

   To interact with the starting points and barriers from the Trace Locations pane in the map view, right-click and choose from the following options:

   • Flash
   • Zoom To
   • Pan To
   • Pop-up
   • Select
   • Unselect

A temporary feature is added to the Trace Locations pane to use in a trace. Because Auto Apply is on, the point is automatically committed as a starting point or barrier for a trace. Starting points and barriers use a temporary feature class named TN_Temp_Starting_Points or TN_Temp_Barriers, respectively, in the project's home geodatabase.

To place additional starting points or barriers, continue clicking other network features. To clear the pane, click the delete button next to each network feature in the pane, or click Clear All to remove all features set as starting points or barriers.

Add selected features from the map view

You can set selected network features on your map as starting points or barriers. Follow the steps below to set trace locations using network features that are already selected on the map.

Note:

By default, the Auto Apply parameter in the Trace Locations pane is unchecked.

1. Select one or more network features on the map that you'll use as starting points.
2. On the Trace Network tab, in the Tools group, click Trace Locations to open the Trace Locations pane.

   Tip:

   Use the Trace Locations drop-down arrow to set the active tab in the pane to be Starting Points or Barriers .

3. In the Trace Locations pane, confirm that the Starting Points or Barriers tab is active.
4. In the Trace Locations pane, click Add selected.

   The selected network features are added to the Trace Locations pane with an asterisk, indicating that they are not committed.

   • A gray circle appears where you clicked to represent a starting point.
   • A gray x appears where you clicked to represent a barrier.
5. Click Apply.

   The gray icons on the map turn green for starting points and red for barriers, indicating that they are ready to be used by a trace. A temporary feature class is created in the project's home geodatabase, either TN_Temp_Starting_Points for starting points or TN_Temp_Barriers for barriers.

A temporary feature is added to the Trace Locations pane to use in a trace for each selected network feature.

To place additional starting points or barriers, continue clicking other network features and click Add selected when you're finished. To clear the pane, click the delete button next to each network feature in the pane, or click Clear All to remove all features set as starting points or barriers.

Specify existing feature classes as starting points and barriers

An existing feature class can be specified for the Starting Points and Barriers parameters in the Trace tool.

1. On the Trace Network tab, in the Tools group, select one of the available trace types from the Trace Network Tool Gallery to open the Trace geoprocessing tool in the Geoprocessing pane.

   The Trace tool is populated with the selected trace type for the trace network in the current active map, and the Starting Points and Barriers parameters are populated with TN_Temp_Starting_Points and TN_Temp_Barriers, respectively.

2. To update the Starting Points parameter, use the drop-down menu to choose from available layers in the map, or browse to an input feature class to serve as starting points.
3. To update the optional Barriers parameter, use the drop-down menu to choose from available layers in the map, or browse to an input feature class to serve as barriers.
4. Configure the remaining options to run the Trace tool.
5. Click Run.

A trace is run using the specified feature layers or feature classes as starting point and barrier features.

Trace Locations pane options

After features are added as starting points and barriers, they are added to the Trace Locations pane. You can interact with these features directly to perform the following tasks:

• To place additional starting points or barriers, continue clicking other network features.
• To remove starting points or barriers, click the delete button next to each network feature in the pane, or click Clear All to remove all features set as starting points or barriers.
• To interact with features in the map view, right-click and choose from the following options:
  • Flash
  • Zoom To
  • Pan To
  • Pop-up
  • Select
  • Unselect

Tracing options

Tracing options allow you to control how trace locations are added to the Trace Locations pane. You can configure these options on the Tracing tab of the Network Options dialog box. To access these options, click the Tracing Options dialog box launcher on the Trace Network tab at the lower right of the Tools group. The Network Options dialog box appears with the Tracing tab active.

The Maximum number of starting points and barriers to add at once parameter specifies the number of trace locations that can be created at the same time without a prompt. The default setting is 10. If more locations are selected on the map or added from a selection to the Trace Locations pane, a dialog box appears asking you to confirm that you want to proceed with the selected number of trace locations.