Establishing global turns
The global turn delay evaluator is only available with ArcGIS 9.3 and higher geodatabases.
The Global Turn Delay Evaluator dialog box is accessed in ArcCatalog or ArcMap through the Network Dataset Properties dialog box.
- Open the Network Dataset Properties dialog box.
- Click the Attributes Tab.
- Select a cost attribute that has a time-based unit (for example, seconds or minutes).
The Evaluators dialog box opens.
- Click the Default Values tab.
Under Type for the Turn element row, choose Global Turn Delay.
The Global Turn Delay option won't be available if your network dataset is not turn-enabled. In this case, you will need to delete and re-create the network dataset, or create a different network, since turns can only be enabled in the New Network Dataset wizard.
Click the Evaluator Properties button .
The following image recaps the last three steps.
The Global Turn Delay Evaluator dialog box opens.
- Choose how to define straight and reverse turns by either accepting the default values or entering new ones in the Turn Angles section of the Global Turn Delay Evaluator dialog box.
- If your network dataset has a hierarchy attribute, you can assign penalties based on the road class of the two edges involved in the turning maneuver. Click Road Classes to open the Global Turn Evaluator Road Class Ranges dialog box.
- Use the dialog box to group the hierarchy levels into three classes: local, secondary, and primary roads.
- Click OK.
- For each turn type in the table at the bottom of the dialog box, type a turn penalty value in the Seconds column.
The Global Turn Delay Evaluator dialog box closes.
The Evaluators dialog box closes.
The Network Dataset Properties dialog box closes.
Now a network analysis that is performed on the network dataset using the time attribute you specified above will include turn penalties from the global turn delay evaluator.
To disable the global turn delay evaluator, change the evaluator type in step 6 from Global Turn Delay to Constant and set its value to zero.