Travel attributes are properties of the network elements that control traversability over the network. Examples of attributes include the time to travel a given length of road, which streets are restricted for which vehicles, the speeds along a given road, and which streets are one-way.
Travel attributes have five basic properties: name, usage type, units, data type, and use by default. Additionally, they have a set of assignments defining the values for the elements:
- The usage type specifies how the attribute will be used during analysis, which is identified as either a cost, descriptor, restriction, or hierarchy.
- Units of a cost attribute are either distance or time units (for example, centimeters, meters, miles, minutes, and seconds).
- Data types can be either Boolean, integer, float, or double. Cost attributes cannot be a Boolean data type. Restrictions are always Boolean, whereas a hierarchy is always an integer.
- Use by default automatically sets those attributes on a newly created network analysis layer.
If a cost, restriction, or hierarchy attribute is set to be used by default, the network analysis layers that are created on the network dataset are set to automatically use that attribute. Only one cost attribute in the network dataset can be set to be used by default. Descriptor attributes cannot be used by default.
Network attributes can also have parameters that can be used by their evaluators. Parameters allow dynamic analysis with network attributes by modeling such characteristics as truck height or weight, weather factors, or current speeds. Restriction attributes always have a parameter named Restriction Usage.
Access travel attributes
Follow the steps below to access the travel attributes from the network dataset property page.
- In the Catalog pane, browse to the folder location where you placed the network dataset.
- Right-click the layer that has a network dataset icon and choose Properties from the context menu. The Network Dataset Properties dialog box appears.
- Click on Travel Attributes. Three tabs, Travel Modes, Costs, and Restrictions, appear.