Network 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, streets that are restricted for certain vehicles, posted speeds along a given road, and one-way streets. Network attributes consist of costs, restrictions, descriptors, hierarchy, and time zones.
Properties and assignments
Network attributes have the following properties: Name, Units, Data Type, and Usage Type. Additionally, they have a set of assignments defining the values for the elements as follows:
- Units of a cost attribute are either distance or time units (for example, centimeters, meters, miles, minutes, and seconds). When the cost attribute is some other unit (for example, dollars, pounds of CO2, or kilowatt hour), Other is used. Additionally, a descriptor attribute can also be speed based.
- The data type can be Boolean, integer, float, or double. Cost attributes cannot be a Boolean data type. Restrictions are always Boolean, and hierarchy and time zone attributes are always integer.
When a network attribute is selected, the information about the travel modes that are using it is displayed as Used By Travel Modes. However, when the selected attribute is not used by a travel mode, this item does not appear.
A network attribute can also be used to calculate the value of another attribute. In this case, a Used By Attributes message displays the names of other attributes that depend on the currently selected network attribute.
Network attributes can be created by accessing the Travel Attributes page on the Network Dataset Properties dialog box. To create network attributes, define the name of the attribute and its usage, units, and data type.
Next, assign evaluators for each source that will provide the values for the network attribute.
Learn more about types of evaluators used by a network
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.
Network attributes can also be edited to accommodate any changes you may want to make to the properties to suit your analysis.
Note:
The best practice for editing network attributes in a network dataset is in a project that does not involve layers that use the network dataset. Some editing may be blocked on the Network Dataset Properties dialog box if there are layers in the project that use this network dataset. It is recommended that you create a blank project, add a connection to the geodatabase that contains the network dataset, and make edits in this project. When the layers using this network dataset are opened in an ArcGIS AllSource session, you will be unable to add, delete, or rename a cost or a restriction attribute. This is to ensure that the network dataset schema updates succeed and that the layers using it are initialized properly when opened.
Access network attributes
Complete the following steps to access the network attributes from the Network Dataset Properties dialog box:
- Open the Network Dataset Properties dialog box.
- Click Travel Attributes. Six tabs appear: Travel Modes, Costs, Restrictions, Descriptors, Time Zone, and Hierarchy.