Every utility network has a network topology. The job of the network topology is to manage information about features and maintain the connectivity between features. For features to connect, they must abide by the feature restrictions of a utility network and applicable network rules must exist.
Information inside of a network topology is stored in a graph persisted as binary pages which allows tracing and diagram functions to read and process information about the network in an efficient manner (as opposed to retrieving information directly from features in a network). Each time a portion of the graph is accessed, that portion is cached and given a time stamp to record the last moment of access. This allows client applications to access the same portion of the graph, avoiding the need to go to the database directly, which can further improve processing time.
States of a network topology
A network topology has two states: enabled and disabled. Only the owner of the utility network can manage these states. To learn how to manage the network topology state, see the Tools and commands section below.
You can use the Enable Network Topology tool to enable the network topology for network functionality, such as tracing and generating diagrams or to generate errors against current network features before registering the dataset as versioned. Discovering errors uses the Only generate errors advanced option and is useful for doing preliminary quality assurance (QA) of the data before the utility network is consumed. After the initial quality assurance of the network data is complete, the utility network feature dataset is registered as branch versioned and you can enable the network topology to allow tracing and network diagram tasks. After the network topology is enabled, dirty areas are created to track certain edits made to network features.
There are different requirements for using the Enable Network Topology tool. To understand the different workflows and requirements for enabling a network topology, see Enable a network topology.
Disable a network topology to perform management tasks such as adding rules or assigning association roles to assets. Disabling a network topology is recommended when loading large amounts of data, as it helps to reduce processing time. When a network topology is disabled, a single dirty area covering the network is created. Dirty areas also remain for any features with errors. Any edits made while the network topology is disabled are not tracked by dirty areas. When the network topology is enabled, all outstanding edits are again validated.
Metadata for the network topology can be found in the Network Topology section of the network properties tab on the Utility Network Properties dialog box. Information such as the current enabled state, dirty area count, time stamps, and duration for network topology actions are maintained as part of the network properties. You can also use the network properties to view the count for errors.
Note:
There are some network configuration tasks that can only be performed before the network topology is enabled for the first time. To learn more, see Utility network management tasks.
Validate a network topology
After a network topology is enabled, portions of the network that have been edited or modified are not represented in the topology until it is validated. The content you see on a map may not be what is stored in the network topology, as the network topology for a given area of a network represents the last time it was enabled or validated (whichever occurred last). Dirty areas are used to mark information that is new to the network and has not been reflected in the network topology. The network topology must be validated to include these changes in tracing and diagram operations.
Validation of a network topology is not an automatic operation that is performed after every edit and only evaluates and processes features with dirty areas that need to be validated. You can initiate the validation process using the Validate command on the Utility Network tab, or by using the Validate Network Topology geoprocessing tool.
See Validate a network topology for more information.
During a validation operation, various network properties, restrictions, and rules are evaluated for all network features in the validation extent. Among the items reviewed are network rules and edge connectivity policies. Issues that are discovered to be causing inconsistent or ambiguous conditions are tracked through errors.
Dirty areas that have associated errors will remain until the error situation is corrected. You can resolve these by making edits to the network feature or by performing configuration changes to allow the error condition. Making configuration changes requires you to disable the network topology.
Dive-in:
The validate operation does not evaluate unlocatable junction and edge objects. The network topology must be disabled and enabled to reflect changes made to these objects.For the list of error situations, see Utility network error IDs.
Two geographical extent options are offered when you initiate the validation process using the Validate command on the Utility Network tab:
- Current Extent—Validates the network topology for features with dirty areas in the part of the network shown in the current extent of the active map. This option is more common and is recommended when edits have been performed in a localized area or work zone.
- Entire Extent—Validates the network topology for features with dirty areas in the entire utility network. Validating the entire extent can involve a potentially heavy operation depending on the size, complexity, and number of dirty areas in your network. This operation is helpful when there are many edits scattered geographically throughout the network that need to be validated. When working with an enterprise geodatabase, it is recommended that you use the Validate Network Topology tool for longer-running validation operations that cover a broad extent or contain a large number of edits, as it takes advantage of asynchronous processing.
When you validate or rebuild a network topology based on a specific extent, the dirty areas that intersect the validation extent are clipped. In the image below, the purple shaded polygons represent dirty areas, and the extent of the validate operation is represented by the black box.
When you validate the network topology based on a specific extent, it is important to be aware of the following:
- The entire dirty area is evaluated when a dirty area associated with an error is partially contained within the validation extent.
- Dirty areas are not clipped when errors are discovered during the validate operation.
- After you validate a topology, dirty areas may still be present if the current extent was validated and it did not encompass all of the dirty areas in the network.
- A network feature is not guaranteed to be valid until the full extent of the feature's dirty area is validated. If there are any dirty areas associated with a network feature, this will impact tracing and update subnetwork operations that use the validate consistency trace configuration option.
When a validate operation is performed, subnetworks that intersect the dirty areas are marked as dirty and the network diagrams are marked as inconsistent. The Update Subnetwork tool is used to update the subnetwork status of a dirty subnetwork and switch subnetwork system diagrams back to a consistent state. You can use the Update Diagram tool to make non-system-generated network diagrams consistent with network features. To learn more about the process for updating subnetworks, see Update a subnetwork.
Rebuild a network topology
Rebuilding the network topology validates and re-creates the network topology for all features in a given area, regardless of whether they have dirty areas. This is similar to how the Enable Network Topology tool behaves, but allows you to run the operation against a specific extent of the network instead of the entire network.
The Rebuild Network Topology tool, along with the Rebuild current extent command in the Network Topology group of the Utility Network tab, allow you to rebuild a specified extent of the network topology to address inconsistencies when you encounter scenarios that prevent a validation operation from completing. Running rebuild on an extent of the network should only be considered when you encounter a scenario in which network analysis does not provide the expected result.
Dirty areas and errors
Dirty areas are created to flag areas that are not reflected in the network topology and to display errors. A network topology is validated to keep the network topology updated and remove dirty areas.
While tracing through a dirty area is allowed, it may yield unexpected results and therefore should not be relied on. Validating the topology for the area that will be traced will clean dirty areas and help ensure trace results reflect what is on the map. To learn more, read about the Validate Consistency option in the Trace tool.
To learn more about these concepts, see Errors and Dirty areas.
Tools and commands
There are several tools and commands used to manage the state of the network topology for a utility network. Some topology management tasks can be performed client/server using data accessed directly from a geodatabase or through services using a feature layer. Regardless of the data source, all of the utility network configuration tools require an active portal connection using the portal utility network owner.
The following geoprocessing tools are provided to work with a network topology:
- Enable Network Topology
- Disable Network Topology
- Validate Network Topology
- Verify Network Topology
- Repair Network Topology
- Rebuild Network Topology
The Enable Network Topology tool can only be run on the Default version. You can enable a network topology to discover errors or to work with dirty areas, network diagrams, and tracing.
The Disable Network Topology tool can be run on the Default version or a user version. You must disable a network topology when performing configuration tasks for a utility network or performing a large data load.
Tip:
If the topology is disabled in a named version, you can use the reconcile process to inherit the topology state from the default branch version.The Validate Network Topology tool, along with the Validate command in the Network Topology group of the Utility Network tab, allow you to validate a network topology for the current extent or the entire geographic extent of a utility network. A validation event (tool or command) can take place in the Default version or a named version by any user who has permissions to edit the version. See Validate a network topology to review both workflows.
The Verify Network Topology tool is used to verify the consistency of a network topology and create an output log file with issues discovered. This tool can be used to discover potential issues in situations in which inconsistencies in the network topology impact the ability to validate.
The Repair Network Topology tool is used to review and perform repairs for consistency of a network topology and create an output log file with the issues discovered and repaired. This tool can be used to discover and repair inconsistencies in the network topology that impact the ability to validate.
The Rebuild Network Topology tool, along with the Rebuild current extent command in the Network Topology group of the Utility Network tab, allow you to rebuild a specified extent of the network topology to address inconsistences when you encounter scenarios that prevent a validation operation from completing.
Application
Through the application of branch versioning, a utility network supports archiving and editor tracking capabilities. This allows edits to the network features and the network topology to be temporally aware. You can perform analytic operations at the current moment or at a specified moment in the past. You must enable the topology at these moments to perform a trace or diagram operation.