Set starting points and barriers

One or more starting points must be used in trace operations in the trace network to define the starting location of a trace. You can also use barriers to represent a location in the network beyond which the trace cannot travel.

In the Trace pane, two options are available for setting starting points and barriers. You can use the Add features option to manually select network features on a map, or you can use the Add selected option to set preselected network features on a map as starting points. The steps below demonstrate these options.

Alternatively, you can specify starting points and barriers using a user-defined feature class or table that meets certain requirements. To learn more, see Starting points and Barriers

Requirements

The network topology must be enabled.

Set starting points and barriers in the Trace pane

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

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

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 a map to set them as starting points or barriers. Complete the steps below if the features you want to set as trace locations are not selected on the map. This workflow uses the default setting in the Trace pane, with Auto Apply checked.

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

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

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

   You can place a starting point or barrier on a 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.

A temporary feature is added to the Starting Points or Barriers tab in the Trace pane for 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 the TN_Temp_Starting_Points or TN_Temp_Barriers temporary feature class, respectively, to store these features in the project's default geodatabase.

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

Add selected features from the map view or attribute table

You can set selected network features on a map as starting points or barriers. Complete the steps below to set trace locations using network features that are selected on the map or in the attribute table to serve as starting points or barriers.

Note:

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

1. Select one or more features on the map to use as starting points or barriers.
2. On the Trace Network tab, in the Tools group, click Trace to open the Trace pane.

   Tip:

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

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

   The selected features are added to the Trace 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 default geodatabase: TN_Temp_Starting_Points for starting points or TN_Temp_Barriers for barriers.

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

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

Specify existing feature classes as starting points and barriers

You can specify an existing feature class for the Starting Points and Barriers parameters in the Trace tool.

1. On the Trace Network tab, in the Tools group, choose one of the available trace types from the Trace Network Tool Gallery to open the Trace 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.

Work with features in the Trace pane

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

• To place additional starting points or barriers, continue clicking other 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 on the tab. The Trace command reveals a Clear All command that can be used to clear all features set as starting points or barriers. This also unselects the active named trace configuration on the Named Configuration tab.
• 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 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 pane, a dialog box appears, prompting you to confirm that you want to proceed with the selected number of trace locations.