Trace utility network

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Discover connected features in a utility network using connected, subnetwork, upstream, and downstream traces.

Image of trace utility network

Use case

You can use a trace to visualize and validate the network topology of a utility network for quality assurance. Subnetwork traces are used for validating whether subnetworks, such as circuits or zones, are defined or edited appropriately.

How to use the sample

Tap on one or more features while 'Add starting locations' or 'Add barriers' is selected. When a junction feature is identified, you may be prompted to select a terminal. When an edge feature is identified, the distance from the tapped location to the beginning of the edge feature will be computed. Select the type of trace using the drop down menu. Tap 'Trace' to initiate a trace on the network. Tap 'Reset' to clear the trace parameters and start over.

How it works

Create a MapView and subscribe to its GeoViewTapped event.
Create and load a ServiceGeodatabase with a feature service URL and get tables by their layer IDs.
Create a Map that contains FeatureLayer(s) created from the ServiceGeodatabase's tables.
Create and load a UtilityNetwork with the same feature service URL and this Map.
Add a GraphicsOverlay with symbology that distinguishes starting locations from barriers.
Identify features on the map and add a Graphic that represents its purpose (starting location or barrier) at the tapped location.
Create a UtilityElement for the identified feature.
Determine the type of this element using its UtilityNetworkSource.SourceType property.
If the element is a junction with more than one terminal, display a terminal picker. Then set the junction's UtilityTerminal property with the selected terminal.
If an edge, set its FractionAlongEdge property using GeometryEngine.FractionAlong.
Add this UtilityElement to a collection of starting locations or barriers.
Create UtilityTraceParameters with the selected trace type along with the collected starting locations and barriers (if applicable).
Set the UtilityTraceParameters.TraceConfiguration with the tier's UtilityTier.GetDefaultTraceConfiguration() result.
Run a UtilityNetwork.TraceAsync with the specified parameters.
For every FeatureLayer in the map, select the features returned with GetFeaturesForElementsAsync from the elements matching their UtilityNetworkSource.FeatureTable with the layer's FeatureTable.

Relevant API

FractionAlong
UtilityAssetType
UtilityDomainNetwork
UtilityElement
UtilityElementTraceResult
UtilityNetwork
UtilityNetworkDefinition
UtilityNetworkSource
UtilityTerminal
UtilityTier
UtilityTraceConfiguration
UtilityTraceParameters
UtilityTraceResult
UtilityTraceType
UtilityTraversability

About the data

The Naperville electrical network feature service, hosted on ArcGIS Online, contains a utility network used to run the subnetwork-based trace shown in this sample.

Additional information

Using utility network on ArcGIS Enterprise 10.8 requires an ArcGIS Enterprise member account licensed with the Utility Network user type extension. Please refer to the utility network services documentation.

Sample Code

TraceUtilityNetwork.cs
Use dark colors for code blocksCopy
﻿// Copyright 2019 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
// language governing permissions and limitations under the License.

using ArcGISRuntime;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Http;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Security;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.UI;
using Esri.ArcGISRuntime.UI.Controls;
using Esri.ArcGISRuntime.UtilityNetworks;
using Foundation;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using UIKit;

namespace ArcGISRuntimeXamarin.Samples.TraceUtilityNetwork
{
    [Register("TraceUtilityNetwork")]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Trace utility network",
        category: "Utility network",
        description: "Discover connected features in a utility network using connected, subnetwork, upstream, and downstream traces.",
        instructions: "Tap on one or more features while 'Add starting locations' or 'Add barriers' is selected. When a junction feature is identified, you may be prompted to select a terminal. When an edge feature is identified, the distance from the tapped location to the beginning of the edge feature will be computed. Select the type of trace using the drop down menu. Tap 'Trace' to initiate a trace on the network. Tap 'Reset' to clear the trace parameters and start over.",
        tags: new[] { "condition barriers", "downstream trace", "network analysis", "subnetwork trace", "trace configuration", "traversability", "upstream trace", "utility network", "validate consistency" })]
    public class TraceUtilityNetwork : UIViewController
    {
        // Hold references to UI controls.
        private MapView _myMapView;
        private UIToolbar _toolbar;
        private UIBarButtonItem _resetButton;
        private UIBarButtonItem _traceButton;
        private UISegmentedControl _startBarrierPicker;
        private UILabel _statusLabel;
        private UIActivityIndicatorView _activityIndicator;
        private UIButton _tracePickerButton;

        // Feature service for an electric utility network in Naperville, Illinois.
        private const string FeatureServiceUrl = "https://sampleserver7.arcgisonline.com/server/rest/services/UtilityNetwork/NapervilleElectric/FeatureServer";

        // Viewpoint in the utility network area.
        private Viewpoint _startingViewpoint = new Viewpoint(new Envelope(-9812980.8041217551, 5128523.87694709, -9812798.4363710005, 5128627.6261982173, SpatialReferences.WebMercator));

        // Utility network objects.
        private UtilityNetwork _utilityNetwork;
        private List<UtilityElement> _startingLocations = new List<UtilityElement>();
        private List<UtilityElement> _barriers = new List<UtilityElement>();
        private UtilityTier _mediumVoltageTier;
        private UtilityTraceType _utilityTraceType;

        // Task completion source for the user selected terminal.
        private TaskCompletionSource<string> _terminalCompletionSource = null;

        // Markers for the utility elements.
        private SimpleMarkerSymbol _startingPointSymbol;
        private SimpleMarkerSymbol _barrierPointSymbol;

        public TraceUtilityNetwork()
        {
            Title = "Trace a utility network";
        }

        private async void Initialize()
        {
            // As of ArcGIS Enterprise 10.8.1, using utility network functionality requires a licensed user. The following login for the sample server is licensed to perform utility network operations.
            AuthenticationManager.Current.ChallengeHandler = new ChallengeHandler(async (info) =>
            {
                try
                {
                    // WARNING: Never hardcode login information in a production application. This is done solely for the sake of the sample.
                    string sampleServer7User = "viewer01";
                    string sampleServer7Pass = "I68VGU^nMurF";

                    return await AuthenticationManager.Current.GenerateCredentialAsync(info.ServiceUri, sampleServer7User, sampleServer7Pass);
                }
                catch (Exception ex)
                {
                    Debug.WriteLine(ex.Message);
                    return null;
                }
            });

            try
            {
                _activityIndicator.StartAnimating();
                _statusLabel.Text = "Loading Utility Network...";

                // Create a map.
                _myMapView.Map = new Map(BasemapStyle.ArcGISStreetsNight)
                {
                    InitialViewpoint = _startingViewpoint
                };

                // Add the layer with electric distribution lines.
                FeatureLayer lineLayer = new FeatureLayer(new Uri($"{FeatureServiceUrl}/3"));
                UniqueValue mediumVoltageValue = new UniqueValue("N/A", "Medium Voltage", new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.DarkCyan, 3), 5);
                UniqueValue lowVoltageValue = new UniqueValue("N/A", "Low Voltage", new SimpleLineSymbol(SimpleLineSymbolStyle.Dash, System.Drawing.Color.DarkCyan, 3), 3);
                lineLayer.Renderer = new UniqueValueRenderer(new List<string>() { "ASSETGROUP" }, new List<UniqueValue>() { mediumVoltageValue, lowVoltageValue }, "", new SimpleLineSymbol());
                _myMapView.Map.OperationalLayers.Add(lineLayer);

                // Add the layer with electric devices.
                FeatureLayer electricDevicelayer = new FeatureLayer(new Uri($"{FeatureServiceUrl}/0"));
                _myMapView.Map.OperationalLayers.Add(electricDevicelayer);

                // Set the selection color for features in the map view.
                _myMapView.SelectionProperties = new SelectionProperties(System.Drawing.Color.Yellow);

                // Create and load the utility network.
                _utilityNetwork = await UtilityNetwork.CreateAsync(new Uri(FeatureServiceUrl), _myMapView.Map);

                // Get the utility tier used for traces in this network. For this data set, the "Medium Voltage Radial" tier from the "ElectricDistribution" domain network is used.
                UtilityDomainNetwork domainNetwork = _utilityNetwork.Definition.GetDomainNetwork("ElectricDistribution");
                _mediumVoltageTier = domainNetwork.GetTier("Medium Voltage Radial");

                // More complex datasets may require using utility trace configurations from different tiers. The following LINQ expression gets all tiers present in the utility network.
                //IEnumerable<UtilityTier> tiers = _utilityNetwork.Definition.DomainNetworks.Select(domain => domain.Tiers).SelectMany(tier => tier);

                // Create symbols for starting locations and barriers.
                _startingPointSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Cross, System.Drawing.Color.LightGreen, 25d);
                _barrierPointSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.X, System.Drawing.Color.OrangeRed, 25d);

                // Create a graphics overlay.
                GraphicsOverlay graphicsOverlay = new GraphicsOverlay();
                _myMapView.GraphicsOverlays.Add(graphicsOverlay);

                // Set the instruction text.
                _statusLabel.Text = "Click on the network lines or points to add a utility element.";
            }
            catch (Exception ex)
            {
                _statusLabel.Text = "Loading Utility Network failed...";
                new UIAlertView("Error", ex.Message, (IUIAlertViewDelegate)null, "OK", null).Show();
            }
            finally
            {
                _activityIndicator.StopAnimating();
            }
        }

        private async void OnGeoViewTapped(object sender, GeoViewInputEventArgs e)
        {
            try
            {
                _activityIndicator.StartAnimating();
                _statusLabel.Text = "Identifying trace locations...";

                // Identify the feature to be used.
                IEnumerable<IdentifyLayerResult> identifyResult = await _myMapView.IdentifyLayersAsync(e.Position, 10.0, false);
                ArcGISFeature feature = identifyResult?.FirstOrDefault()?.GeoElements?.FirstOrDefault() as ArcGISFeature;
                if (feature == null) { return; }

                // Create element from the identified feature.
                UtilityElement element = _utilityNetwork.CreateElement(feature);

                if (element.NetworkSource.SourceType == UtilityNetworkSourceType.Junction)
                {
                    // Select terminal for junction feature.
                    IEnumerable<UtilityTerminal> terminals = element.AssetType.TerminalConfiguration?.Terminals;
                    if (terminals?.Count() > 1)
                    {
                        element.Terminal = await WaitForTerminal(terminals);
                    }
                    _statusLabel.Text = $"Terminal: {element.Terminal?.Name ?? "default"}";
                }
                else if (element.NetworkSource.SourceType == UtilityNetworkSourceType.Edge)
                {
                    // Compute how far tapped location is along the edge feature.
                    if (feature.Geometry is Polyline line)
                    {
                        line = GeometryEngine.RemoveZ(line) as Polyline;
                        element.FractionAlongEdge = GeometryEngine.FractionAlong(line, e.Location, -1);
                        _statusLabel.Text = $"Fraction along edge: {element.FractionAlongEdge}";
                    }
                }

                // Check whether starting location or barrier is added to update the right collection and symbology.
                Symbol symbol = null;
                if (_startBarrierPicker.SelectedSegment == 0)
                {
                    _startingLocations.Add(element);
                    symbol = _startingPointSymbol;
                }
                else
                {
                    _barriers.Add(element);
                    symbol = _barrierPointSymbol;
                }

                // Add a graphic for the new utility element.
                Graphic traceLocationGraphic = new Graphic(feature.Geometry as MapPoint ?? e.Location, symbol);
                _myMapView.GraphicsOverlays.FirstOrDefault()?.Graphics.Add(traceLocationGraphic);
            }
            catch (Exception ex)
            {
                _statusLabel.Text = "Identifying locations failed...";
                new UIAlertView("Error", ex.Message, (IUIAlertViewDelegate)null, "OK", null).Show();
            }
            finally
            {
                if (_statusLabel.Text.Equals("Identifying trace locations...")) { _statusLabel.Text = "Could not identify location."; }
                _activityIndicator.StopAnimating();
            }
        }

        private async Task<UtilityTerminal> WaitForTerminal(IEnumerable<UtilityTerminal> terminals)
        {
            try
            {
                // Prevent user from tapping map while selecting terminal.
                _myMapView.GeoViewTapped -= OnGeoViewTapped;

                // Start the UI for the user choosing the junction.
                UIAlertController prompt = UIAlertController.Create(null, "Choose terminal", UIAlertControllerStyle.ActionSheet);

                foreach (UtilityTerminal terminal in terminals)
                {
                    prompt.AddAction(UIAlertAction.Create(terminal.Name, UIAlertActionStyle.Default, Choose_Click));
                }

                // Needed to prevent crash on iPad.
                UIPopoverPresentationController ppc = prompt.PopoverPresentationController;
                if (ppc != null)
                {
                    ppc.SourceView = _toolbar;
                    ppc.PermittedArrowDirections = UIPopoverArrowDirection.Down;
                    ppc.DidDismiss += (s, e) => _terminalCompletionSource.TrySetCanceled();
                }

                PresentViewController(prompt, true, null);

                // Wait for the user to select a terminal.
                _terminalCompletionSource = new TaskCompletionSource<string>();
                string selectedName = await _terminalCompletionSource.Task;
                return terminals.Where(x => x.Name.Equals(selectedName)).FirstOrDefault();
            }
            finally
            {
                // Enable the main UI again.
                _myMapView.GeoViewTapped += OnGeoViewTapped;
            }
        }

        private void Choose_Click(UIAlertAction action)
        {
            _terminalCompletionSource.TrySetResult(action.Title);
        }

        private void ChangeTraceType(object sender, EventArgs e)
        {
            // Prevent user from tapping map while selecting a trace type.
            _myMapView.GeoViewTapped -= OnGeoViewTapped;

            // Start the UI for the user choosing the trace type.
            UIAlertController prompt = UIAlertController.Create(null, "Choose trace type", UIAlertControllerStyle.ActionSheet);

            // Add a selection action for every valid trace type.
            foreach (string name in new string[] { "Connected", "Subnetwork", "Upstream", "Downstream" })
            {
                prompt.AddAction(UIAlertAction.Create(name, UIAlertActionStyle.Default, TraceTypeClick));
            }

            // Needed to prevent crash on iPad.
            UIPopoverPresentationController ppc = prompt.PopoverPresentationController;
            if (ppc != null)
            {
                ppc.SourceView = _tracePickerButton;
                ppc.PermittedArrowDirections = UIPopoverArrowDirection.Down;
            }

            PresentViewController(prompt, true, null);

            // Enable the main UI again.
            _myMapView.GeoViewTapped += OnGeoViewTapped;
        }

        private void TraceTypeClick(UIAlertAction action)
        {
            _utilityTraceType = (UtilityTraceType)Enum.Parse(typeof(UtilityTraceType), action.Title);
            _tracePickerButton.SetTitle($"Trace type: {_utilityTraceType}", UIControlState.Normal);
        }

        private async void OnTrace(object sender, EventArgs e)
        {
            try
            {
                // Update the UI.
                _activityIndicator.StartAnimating();
                _statusLabel.Text = $"Running {_utilityTraceType.ToString().ToLower()} trace...";

                // Clear previous selection from the layers.
                _myMapView.Map.OperationalLayers.OfType<FeatureLayer>().ToList().ForEach(layer => layer.ClearSelection());

                // Build trace parameters.
                UtilityTraceParameters parameters = new UtilityTraceParameters(_utilityTraceType, _startingLocations);
                foreach (UtilityElement barrier in _barriers)
                {
                    parameters.Barriers.Add(barrier);
                }

                // Set the trace configuration using the tier from the utility domain network.
                parameters.TraceConfiguration = _mediumVoltageTier.GetDefaultTraceConfiguration();

                //  Get the trace result from the utility network.
                IEnumerable<UtilityTraceResult> traceResult = await _utilityNetwork.TraceAsync(parameters);
                UtilityElementTraceResult elementTraceResult = traceResult?.FirstOrDefault() as UtilityElementTraceResult;

                // Check if there are any elements in the result.
                if (elementTraceResult?.Elements?.Count > 0)
                {
                    foreach (FeatureLayer layer in _myMapView.Map.OperationalLayers.OfType<FeatureLayer>())
                    {
                        IEnumerable<UtilityElement> elements = elementTraceResult.Elements.Where(element => element.NetworkSource.Name == layer.FeatureTable.TableName);
                        IEnumerable<Feature> features = await _utilityNetwork.GetFeaturesForElementsAsync(elements);
                        layer.SelectFeatures(features);
                    }
                }
                _statusLabel.Text = "Trace completed.";
            }
            catch (Exception ex)
            {
                _statusLabel.Text = "Trace failed...";
                if (ex is ArcGISWebException && ex.Message == null)
                {
                    new UIAlertView(ex.GetType().Name, "Trace failed.", (IUIAlertViewDelegate)null, "OK", null).Show();
                }
                else
                {
                    new UIAlertView(ex.GetType().Name, ex.Message, (IUIAlertViewDelegate)null, "OK", null).Show();
                }
            }
            finally
            {
                _activityIndicator.StopAnimating();
            }
        }

        private void OnReset(object sender, EventArgs e)
        {
            // Reset the UI.
            _statusLabel.Text = "Click on the network lines or points to add a utility element.";
            _activityIndicator.StopAnimating();

            // Clear collections of starting locations and barriers.
            _startingLocations.Clear();
            _barriers.Clear();

            // Clear the map of any locations, barriers and trace result.
            _myMapView.GraphicsOverlays.FirstOrDefault()?.Graphics.Clear();
            _myMapView.Map.OperationalLayers.OfType<FeatureLayer>().ToList().ForEach(layer => layer.ClearSelection());
        }

        public override void LoadView()
        {
            // Create the views.
            View = new UIView() { BackgroundColor = ApplicationTheme.BackgroundColor };

            _myMapView = new MapView();
            _myMapView.TranslatesAutoresizingMaskIntoConstraints = false;

            _statusLabel = new UILabel
            {
                Text = "Instructions",
                AdjustsFontSizeToFitWidth = true,
                TextAlignment = UITextAlignment.Center,
                BackgroundColor = UIColor.FromWhiteAlpha(0, .6f),
                TextColor = UIColor.White,
                Lines = 1,
                TranslatesAutoresizingMaskIntoConstraints = false
            };

            _tracePickerButton = new UIButton(UIButtonType.System);
            _tracePickerButton.SetTitle("Trace type: Connected", UIControlState.Normal);
            _tracePickerButton.TranslatesAutoresizingMaskIntoConstraints = false;

            _startBarrierPicker = new UISegmentedControl(new string[] { "Start", "Barrier" });
            _startBarrierPicker.SelectedSegment = 0;

            _traceButton = new UIBarButtonItem();
            _traceButton.Title = "Trace";

            _resetButton = new UIBarButtonItem();
            _resetButton.Title = "Reset";

            _toolbar = new UIToolbar();
            _toolbar.TranslatesAutoresizingMaskIntoConstraints = false;
            _toolbar.Items = new[]
            {
                new UIBarButtonItem(_startBarrierPicker),
                new UIBarButtonItem(UIBarButtonSystemItem.FlexibleSpace),
                _traceButton,
                _resetButton
            };

            _activityIndicator = new UIActivityIndicatorView(UIActivityIndicatorViewStyle.WhiteLarge)
            {
                TranslatesAutoresizingMaskIntoConstraints = false,
                HidesWhenStopped = true,
                BackgroundColor = UIColor.FromWhiteAlpha(0, .5f)
            };

            // Add the views.
            View.AddSubviews(_myMapView, _statusLabel, _tracePickerButton, _toolbar, _activityIndicator);

            // Lay out the views.
            NSLayoutConstraint.ActivateConstraints(new[]
                {
                    _myMapView.TopAnchor.ConstraintEqualTo(View.SafeAreaLayoutGuide.TopAnchor),
                    _myMapView.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                    _myMapView.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                    _myMapView.BottomAnchor.ConstraintEqualTo(_tracePickerButton.TopAnchor),

                    _tracePickerButton.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                    _tracePickerButton.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                    _tracePickerButton.BottomAnchor.ConstraintEqualTo(_toolbar.TopAnchor),
                    _tracePickerButton.HeightAnchor.ConstraintEqualTo(40),

                    _toolbar.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                    _toolbar.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                    _toolbar.BottomAnchor.ConstraintEqualTo(View.SafeAreaLayoutGuide.BottomAnchor),

                    _statusLabel.TopAnchor.ConstraintEqualTo(_myMapView.TopAnchor),
                    _statusLabel.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                    _statusLabel.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                    _statusLabel.HeightAnchor.ConstraintEqualTo(40),

                    _activityIndicator.TopAnchor.ConstraintEqualTo(_statusLabel.BottomAnchor),
                    _activityIndicator.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                    _activityIndicator.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                    _activityIndicator.BottomAnchor.ConstraintEqualTo(View.BottomAnchor)
                }
            );
        }

        public override void ViewWillAppear(bool animated)
        {
            base.ViewWillAppear(animated);

            // Subscribe to events.
            _myMapView.GeoViewTapped += OnGeoViewTapped;
            _traceButton.Clicked += OnTrace;
            _resetButton.Clicked += OnReset;
            _tracePickerButton.TouchUpInside += ChangeTraceType;
        }

        public override void ViewDidDisappear(bool animated)
        {
            base.ViewDidDisappear(animated);

            // Unsubscribe from events, per best practice.
            _myMapView.GeoViewTapped -= OnGeoViewTapped;
            _traceButton.Clicked -= OnTrace;
            _resetButton.Clicked -= OnReset;
            _tracePickerButton.TouchUpInside -= ChangeTraceType;
        }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            Initialize();
        }
    }
}