Analyze and resolve topology errors

In this tutorial, you'll assume the role of a GIS analyst at a small municipality who is tasked with implementing a utility network. The utility network that you'll work with was migrated from a geometric network, which means it is a utility network with limited configuration, and a data model that is different from the industry standard models. You've discovered that the data contains thousands of topology errors. You know that getting through this process takes time and patience, but you aren’t sure where to start and what tools or resources are available to make this process easier. You'll learn how to identify data quality issues and determine which ones require source data cleanup and which ones are appropriate for automated data cleanup. Then, you'll learn how to perform automated data correction for your topology errors.

This tutorial was last tested on February 27, 2026, using ArcGIS Pro 3.5.6. If you're using a different version of ArcGIS Pro, you may encounter different functionality and results.

Requirements

• ArcGIS Pro (see options for software access)

Analyze a utility network

You'll learn how to use the Analyze Network Data tool and its output to analyze and review the topology errors associated with your utility network data. This is an efficient way to identify any important topological errors that you need to resolve to build a fully connected utility network.

Analyze the network data

First, you'll create an analysis database and layer file that describes all the topology errors in your utility network.

1. Download the Analyze_and_resolve_topology_errors project package.

   A file named Analyze_and_resolve_topology_errors.ppkx is downloaded to your computer.

2. Locate the downloaded file on your computer and double-click it to open it. If prompted, sign in with your ArcGIS account credentials.

   Note:

   If you don't have access to ArcGIS Pro or an ArcGIS organizational account, see options for software access.

   The project appears with a map showing the migrated data with the default symbology.

   

   Note:

   The data was migrated from a geometric network using the Migrate To Utility Network tool.

   Since the data were migrated into a new utility network, you'll analyze the date to locate any issues.

3. On the ribbon, click the Analysis tab. In the Geoprocessing group, click Tools.

   

   The Geoprocessing pane appears.

4. For Find Tools, type analyze network. In the list of results, click the Analyze Network Data tool.

   

   The Analyze Network Data tool appears and requires some basic parameters, mainly the utility network you want to analyze.

5. For Input Utility Network, click the drop-down menu and choose the utility network from the current map.

   

   Note:

   Choosing the Set default resolution actions option will populate some error resolutions with default actions.

   You'll leave the Output Location and Output Name parameters unchanged. Running this tool will create a folder and geodatabase in the Output Location directory using the name specified (AnalysisResults) in the Output Name parameter.

6. Click Run.

   Additional layers appear on the map showing the results of the analysis.

   

   In the Contents pane, you can view the symbology for any errors.

   

   Next, you'll turn the source layers off to focus on the analysis results.

7. In the Contents pane, turn off the Migration Database layer.

   

   Turning off the source layers will make it easier to view the errors on the map.

   

   Now you can clearly see only the locations where the tool has identified errors.

Review the results

Next, you'll explore the various outputs from the Analyze Network Data tool and learn their purpose. It's good practice to review all the outputs of the tool before you perform any data corrections.

1. In the Contents pane, locate the Error Summary layer.

   

   Each error is color-coded based on the Error Code value. The colors are consistent across all the layers and charts the tool created. All error features on the map are color coded using the type of error they represent.

2. On the ribbon, click the Map tab. In the Selection group, click the Select tool.

   

3. Use the Select tool to select one of the dark green missing junction features.

   

   When you select one of the missing junction features, many are selected. These are multi-part features which allow one feature to have many geometries. Each error summary feature represents a collection of features that share a common problem.

   When an error summary feature is selected, the error resolution features associated with it are automatically selected.

4. On the ribbon, click the Edit tab. In the Selection group, click Attributes.

   

5. In the Attributes pane, under AnalysisResults : Error Summary, click the Missing junction (mid-end) feature to see its attributes.

   

   The selected point represents one of 34 missing junctions between the Domestic Water Lateral Lines and Water Mains layers.

   • The Error code field indicates the type of error that was discovered.
   • The Analysis types field shows all the feature types that are at the location where the error was found, including features that are coincident but do not have an error.
   • The Types in error field shows the types of features that generated the error, in this case a curb stop valve and a distribution network junction.
   • The Occurrences field shows how many instances of this type of error are found with these combinations of features.
   • The Error Summary feature is a multipoint geometry that contains a point for each location where a combination of features meets these criteria.
6. On the Map tab, in the Selection group, click Clear.

   

7. In the Contents pane, turn on the Error Locations layer.

   

   The Error Locations layer shows the individual features for each error location instead of a summary feature for all the errors locations, so it shows the errors as separate features, not multi-part.

8. Turn on the MigrationDatabase layer.

   Turning on this layer allows you to see the features from the migrated data alongside the error features.

9. On the Map tab, click Bookmarks and choose Missing Junction bookmark.

   

   The map zooms to a missing junction.

   

   This bookmark show an error location feature for one of the missing junction errors you reviewed earlier.

10. Using the Select tool, click the Error Location feature (push pin) to select it.

    

    Selecting the Error Location feature automatically selects the related features in the map. This will select the lines that are responsible for the missing junction error.

    Error locations are often used to communicate locations that require manual data cleanup. If your editors are using ArcGIS Pro, you can share this layer file and the AnalysisResults geodatabase with them. If your editors can only use ArcMap, because of a geometric network, you must copy the relevant error features to a new file geodatabase.

11. Clear the selection.
12. In the Contents pane, double-click the Occurrences by Error chart.

    

    The Chart Properties pane appears and the chart displays below the map.

    

    The Occurrences by Error chart shows how many occurrences there are for each type of error.

13. Open the Occurrences by Error and Types chart.

    

    The chart shows how many different combinations of features are associated with each error.

14. Close the charts and the Chart Properties pane.
15. On the Quick Access Toolbar, click the Save Project button.

    

Now that you understand the purpose of each of the layers and how they are used to review topology errors in a utility network, you are ready to review all the errors and determine their resolutions.

Specify error resolutions

Each unique combination of errors and types identified by this tool provides an opportunity to resolve a problem with your data. To resolve an error through automation, you must populate one or more actions on the error resolution records and run the Apply Error Resolutions tool. If you want to leave an error unresolved so a user can fix it in the source data, or resolve it manually in the utility network, then you can leave the action with the default value of Do Nothing.

Next, you'll review each error in the Error Summary layer and populate the actions on their corresponding error resolutions. The actions you use to resolve an error may be different, depending on whether you are resolving an error for a prototype or for a production migration. As an example, you may decide to delete stacked point features when creating a prototype of a utility network. For your final production migration you want to offset the stacked point features or leave them unresolved, so editors must manually review and correct stacked point features after migration.

All your edits will be to the error analysis layers and database. The migrated utility network data is not modified until the last part of this tutorial, when you run the Apply Error Resolutions tool.

Review the error summaries

Before you make any edits, you'll learn how to review each of the errors in the Attributes pane. This is one of many ways to review data, but is often used when you must keep track of one set of features you are reviewing while allowing you to freely select and manipulate other features in the map.

1. On the ribbon, in the Selection group, click Attributes.

   The Attributes pane appears. Currently, there are no selected features.

   

   The Selection tab is used to review attributes for any currently selected rows.

2. Click the Layers tab.

   The Layers tab is used to review the contents of a single layer on the map. This tab allows you to browse all the records in a layer. The list found under the Layers tab is unique in that it remembers which record you were reviewing even when the current map selection changes.

3. For Choose a layer, click the drop-down arrow and choose the AnalysisResults:Error Summary layer.

   

   The Attributes pane updates to show the active Error Summary features.

   

   All the layers created by the Analyze Network Data tool have definition queries that allow you to filter their contents to look at specific error codes. By default, each layer has the UN errors definition query applied. This definition query will filter out any lower-severity issues that do not create topology errors or cause connectivity problems.

4. In the Contents pane, select the Error Summary layer.

   

   You'll review or modify the layer's definition query.

5. On the ribbon, click the Data tab.

   In the Definition Query group, you can see the UN errors definition query is applied to the layer.

   

   This definition query filters out quality assurance related issues that do not create topology error or connectivity issues.

6. For the active definition query, click the drop-down arrow.

   

   Each of these definition queries corresponds to one or more error codes identified by the Analyze Network Data tool. You can change the active definition query at any time to display different features.

   Instead of reviewing all the errors at once, you'll focus on reviewing and providing resolutions for one error code at a time. This will make it easier to ensure you are consistently applying the same kinds of resolutions to similar errors and that you don't miss applying a resolution to one of the error summaries for a particular type of error.

Resolve missing junctions

Missing junction errors are caused when two or more different types of lines are drawn in a way that they could be connected, but there isn't a device or junction that allows them to be connected. The most common resolution for this is to create a junction that allows the features to connect.

1. If necessary, in the Contents pane, select the Error Summary layer. On the ribbon, click the Data tab.
2. In the Definition Query group, set the definition query to No junction (end).

   

   By changing the definition query, you'll be able to see the missing junctions at the endpoints of lines. These are situations where the endpoints of multiple lines are connected without a junction feature.

3. In the Attributes pane, select the first missing junction record.

   

   This is the most common error, with the first summary record accounting for most of the errors in the database. There are 633 occurrences where a hydrant lateral line is snapped to a water main without any kind of fitting.

4. Expand the missing junction feature so you can see its associated error resolutions.

   

   Expanding the Error Summary feature allows you to see the error resolutions available to resolve the problem. Each resolution allows you to apply a corrective action to the feature. Depending on the situation, you may specify an action for one, or all the records. Currently, there are no actions associated with these features because their display expression says Do nothing.

5. Click the Water Lateral Lines/Hydrant error resolution.

   

6. In the list of attributes, populate the following values:
   • For Action, click the current value and choose Create.
   • For Create/Update type, click the current value and choose WaterJunction/Water Fittings/Tee.

   

7. Click Apply.

   Note:

   Do not specify more than one Create action for an error. Otherwise, you'll create stacked point features.

   Next, you'll choose an error resolution for the next missing junction (end-end) feature.

8. Expand the Missing junction (end-end) [40] feature and expand Error Resolutions.
9. Click the Water Lateral Lines/Fire – Do nothing resolution.
10. Set Action to Create and Create/Update type to WaterJunction/Water Fittings/Tee.
11. Enable Auto Apply.

    

    Now that you have done two of the resolutions, you'll finish the remaining missing junction errors using the same values. Only do one resolution per missing junction feature to avoid duplicates.

12. Complete the same resolution for the remaining Missing Junction (end-end) errors, using the following parameters as a guide:
    • Missing junction (end-end) [28] – for the error resolution Water Lateral Lines/Fire, set Action to Create and Create-update type to WaterJunction/Water Fittings/Tee.
    • Missing junction (end-end) [6] – for the error resolution Water Lateral Lines/Domestic, set Action to Create and Create-update type to WaterJunction/Water Fittings/Tee.
    • Missing junction (end-end) [4] – for the error resolution Water Lateral Lines/Domestic, set Action to Create and Create-update type to WaterJunction/Water Fittings/Tee.
    • Missing junction (end-end) [2] – for the error resolution Water Lateral Lines/Commercial, set Action to Create and Create-update type to WaterJunction/Water Fittings/Tee.
    • For each of the remaining Missing junction (end-end) [2] errors, select the first error resolution and set Action to Create and Create-update type to WaterJunction/Water Fittings/Tee.

    

13. In the Contents pane, confirm that the Error Summary layer is selected. On the ribbon, click the Data tab.
14. In the Definition Query group, set the definition query for the Error Summary layer to No junction (mixed).

    

    This definition query will display features where the endpoint of one line connects midspan on another line without a junction or device. You'll fix these errors similarly to how you fixed the other errors.

15. In the Attributes pane, for each of the Missing junction (mid-end) errors, do the following:
    • Expand Error Resolutions
    • Select the first error resolution.
    • Set Action to Create and Create/Update type to WaterJunction/Water Fittings/Tee.
    • Click Apply.

    

16. On the ribbon, on the Edit tab, in the Manage Edits group, click Save.

    

17. Click Yes to confirm saving the edits.

    You reviewed all the missing junctions that will cause topology errors. You did not review or provide resolutions for any No junction (mid) features because these features are included for informational purposes only.

    A No junction (mid) feature is created whenever two lines share a common vertex midspan on each line. The utility network will not establish connectivity between these features, nor will it create a topology error. In some cases, you may want to review these locations to ensure that the features should not be connected, or you may even have a cartographic standard that doesn't allow for this.

    You can find examples of the different resolutions for this issue in the Resolving topology errors article.

Resolve stacked points

Next, you'll review all the areas where stacked point features were discovered. Stacked points are when two or more devices or junctions, that don't belong to a structure network, occupy the same location.

1. In the Definition Query group, set the definition query for the layer to Stacked points.

   

2. In the Attributes pane, select the first Stacked points error and expand Error Resolutions.

   

   The first Error Summary is for a single occurrent of a Water Curb Stop Valve feature stacked on top of a WaterDistribution_Net_Junctions feature. In this instance, a curb stop valve is stacked (coincident) with a water distribution network junction.

3. Select the WaterDistribution_Net_Junctions error resolution.

   

4. Set the Action to Delete all.

   

   This action will delete the network junction while keeping the curb stop valve.

5. Repeat the same steps for the second Stacked points error.
6. Save your edits.

   You reviewed all the stacked point features. For each scenario, you ensured that only one feature was left in place by deleting the other feature. You can find examples of the different resolutions for this issue in the Resolving topology errors article.

Resolve snapping issues

Next, you'll review situations where multiple features are extremely close to each other but are not close enough that they can be consistently connected. These are called vertex within tolerance features. These features will not create topology errors, but if they aren't resolved, then can end up being disconnected when you attempt to trace the network.

To resolve these issues, you'll set one feature to act as an anchor and the other nearby features to snap to that feature.

1. On the Data tab, In the Definition Query group, set the definition query for the layer to Vertex tolerance.

   

   This option will show all the locations where two or more features are close to each other but not snapped.

2. In the Attributes pane, expand the first Vertex within tolerance error and expand Error Resolutions.

   

   This error represents two locations where system valves aren't properly snapped to nearby water mains.

3. Select the Water Mains/WaterMains error resolution.
4. Set Action to Anchor.

   

   This option ensures the geometry of the water main will not be affected by the error resolution.

5. Select the Water System Valves/Water System Valves error resolution and set Action to Snap.

   

   This option will snap the water system valve to the vertex on the nearby water main.

6. For the second Vertex within tolerance error, set the following:
   • For Water Fittings/Tap, set Action to Snap.
   • For Water Lateral Lines/Hydrant, set Action to Snap.
   • For Water Mains/Water Mains, set Action to Anchor.

   

   This resolution will keep the vertices of the water main in the same location and snap the endpoint of the lateral and the water fitting to that vertex.

7. Save your edits.

   You reviewed all the vertex tolerance features that can cause connectivity issues. For each scenario you ensured that all the features would be snapped to a single anchor feature. In these examples you chose to snap any junctions or devices to lines, but depending on your organization's standards you could also have chosen to use a particular junction or device feature as the anchor location. You can find examples of the different resolutions for this issue in the Resolving topology errors article.

Now that you've specified at least one action for each error summary, you have defined a plan that can be used to correct problems with your data.

Apply error resolutions to the network

Next, you'll apply the error resolutions you defined to the migrated data. This step is important as it allows you to verify that the planned actions you defined earlier successfully resolve all the errors in the network.

Because you defined actions for all your problems, you can use the Enable Network Topology tool to build the topology and confirm this. If you decided to leave some issues for manual cleanup, you could either run the Analyze Network Data tool a second time to confirm the expected issues remain, or you could enable the network topology and be prepared to manually resolve the resulting topology errors.

Apply the error resolutions

Up to this point you have used the results of the Analyze Network Data tool to provide instructions for how you would like to resolve the errors. You'll use the Apply Error Resolutions tool to perform the actions you specified on each error resolution.

1. In the Geoprocessing pane, search for and open the Apply Error Resolutions tool.

   

2. For Input Utility Network, click the drop-down arrow and choose the utility network that is listed.
3. For Resolution Table, choose Analysis Results/Error Resolutions.

   Note:

   It is important that you use the Error Resolutions table in the current map because it has a definition query applied to it to filter out unnecessary resolutions.

   

   You don't have to populate the Output Location or Output Name parameters to run the tool. These optional parameters cause the tool to generate an edit log that records all the edits made to the layers in the utility network.

   Note:

   If you only want to apply some of your error resolutions, you can select the corresponding records when you run this tool. In that case, the Use filtered records message indicator will be replaced with an indicator for Use the selected records.

4. Click Run.

   Once the tool finishes, you are ready to verify that the tool fixed all the issues in the data that could result in topology errors.

Enable the network topology

You can verify that you have a valid topology by enabling the network topology.

1. Search for and open the Enable Network Topology (Utility Network) tool.

   

2. For Input Utility Network, choose the only available network.

   

3. Click Run.
4. In the Contents pane, right-click the Network Utility Network and choose Properties.

   

5. Click the Network Properties tab.

   

6. In the Network Topology section, confirm that there are no errors or dirty areas in the topology.

   

   The topology contains no errors or dirty areas.

7. Close the properties window and save the project.

   You have enabled a topology on the network and checked it for errors. All the resolutions you specified worked and didn't cause additional issues. If you'd like to learn more, check out the following resources:

   • If you want to learn how the data for this tutorial was migrated, check out the Utility network migration wizard walkthrough article.
   • This tutorial was based on the Analyzing Topology Errors and Resolving topology errors articles.
   • To learn more about utility network data migration, check out the ArcGIS Utility Network migration reading list article.
   • For industry-specific resources on the utility network, check out the Getting started with the utility network series.

In this tutorial, you learned how to identify topology issues in a utility network and explored the database that describes those issues. You reviewed each error summary and ensured an appropriate action was taken on the corresponding error features. Then, you applied the error resolutions using a geoprocessing tool. Finally, you were able to confirm that the actions you defined were all appropriate resolutions by enabling the network topology and confirming that the resulting topology is error-free.

You can find more tutorials in the tutorial gallery.

Acknowledgements

• Map data used with permission from the City of Naperville.
• World Topographic Map sources: Esri, TomTom, Garmin, FAO, NOAA, USGS, OpenStreetMap contributors, and the GIS User Community
• World Hillshade layer sources: Esri, Vantor, Airbus DS, USGS, NGA, NASA, CGIAR, N Robinson, NCEAS, NLS, OS, NMA, Geodatastyrelsen, Rijkswaterstaat, GSA, Geoland, FEMA, Intermap, and the GIS user community
• © 2024 Adobe Stock. All rights reserved.