Adding a hierarchy to a network dataset
To perform an analysis using hierarchies, the network dataset needs to have a hierarchy network attribute. To set the hierarchy attribute, follow these steps:
- In ArcCatalog, use the Catalog tree to find your network dataset.
- Right-click the network dataset and choose Properties to open the Network Dataset Properties dialog box.
- Click the Attributes tab.
- Click Add to open the Add New Attribute dialog box.
- In the Name text box, type a name for your hierarchy.
- Choose Hierarchy in the Usage Type drop-down list.
- Choose whether or not to use the hierarchy by default.
- Click OK.
- On the Network Dataset Properties dialog box, choose the hierarchy network attribute you just created and click Evaluators.
- Specify how the values that will be used to rank network edges into hierarchy classes should be assigned. This is done by choosing the proper Type and Value information on the Evaluators dialog box and, if necessary, filling in the required information in the text boxes on the Field Evaluators dialog box.
- Click OK to return to the Network Dataset Properties dialog box.
If you plan to use the global turn delay evaluator with your hierarchical network dataset, you need to classify the hierarchy levels into primary, secondary, and local roads. To do so, follow these substeps:
- Click Ranges.
The Hierarchy Ranges dialog box opens.
The highest levels of a network hierarchy have the lowest integer values. This dialog box is designed to allow you to classify one or more hierarchy levels into each of the three categories.
- Classify the hierarchy network attribute values into ranges for primary, secondary, and local roads by clicking the arrow buttons labeled up to and and higher.
- Click OK to close the Hierarchy Ranges dialog box.
- Click Ranges.
- Click OK to close the Network Dataset Properties dialog box.