Add a feature layer

Before starting this tutorial:

• You need an ArcGIS Location Platform or ArcGIS Online account.

• Ensure your development environment meets the system requirements.

Optionally, you may want to install the ArcGIS Maps SDK for .NET to get access to project templates in Visual Studio (Windows only) and offline copies of the NuGet packages.

Option 1: Develop the code

To start the tutorial, complete the Display a map tutorial. This creates a map to display the Santa Monica Mountains in California using the topographic basemap from the ArcGIS basemap styles service.

Open a Visual Studio solution

1. Open the Visual Studio solution you created by completing the Display a map tutorial.
2. Continue with the following instructions to add feature layers that will display above the basemap.

Update the tutorial name used in the project (optional)

The Visual Studio solution, project, and the namespace for all classes currently use the name DisplayAMap. You can rename these if you prefer them to reflect the current tutorial. Renaming is not required, your code will still work if you keep the original name.

Create URIs to reference feature service data

To display three new data layers (also known as operational layers) on top of the current basemap, you will create FeatureLayers using URIs to reference datasets hosted in ArcGIS Online.

1. Open a browser and navigate to the URL for Parks and Open Spaces to view metadata about the layer. To display the layer in your app, you only need the URL.

   ArcGIS REST Services Directory

   The ArcGIS REST Services Directory page provides information such as the geometry type, the geographic extent, the minimum and maximum scale at which features are visible, and the attributes (fields) it contains. You can preview the layer by clicking on ArcGIS.com Map in the "View In:" list at the top of the page.

2. In the Visual Studio > Solution Explorer, double-click MapViewModel.cs to open the file.

   Model-View-ViewModel (MVVM) design pattern

   The project uses the Model-View-ViewModel (MVVM) design pattern to separate the application logic (view model) from the user interface (view). MapViewModel.cs contains the view model class for the application, called MapViewModel. See the Microsoft documentation for more information about the Model-View-ViewModel pattern.

3. In the SetupMap() function, add code that defines the URIs to the hosted layers. You will add: Trailheads (points), Trails (lines), and Parks and Open Spaces (polygons).

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           private void SetupMap()
           {
               // Create a new map with a 'topographic vector' basemap.
               Map map = new Map(BasemapStyle.ArcGISTopographic);
   
               // Set the initial viewpoint around the Santa Monica Mountains in California.
               var mapCenterPoint = new MapPoint(-118.805, 34.027, SpatialReferences.Wgs84);
               map.InitialViewpoint = new Viewpoint(mapCenterPoint, 100000);
   
               // Set the view model's Map property with the map.
               Map = map;
   
               var parksUri = new Uri(
                   "https://services3.arcgis.com/GVgbJbqm8hXASVYi/ArcGIS/rest/services/Parks_and_Open_Space/FeatureServer/0"
                   );
   
               var trailsUri = new Uri(
                   "https://services3.arcgis.com/GVgbJbqm8hXASVYi/ArcGIS/rest/services/Trails/FeatureServer/0"
                   );
   
               var trailheadsUri = new Uri(
                   "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trailheads/FeatureServer/0"
                   );
   

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Create feature layers to display the hosted data

You will create three new FeatureLayer to display the hosted layer at each URI.

1. In the SetupMap() function, create new feature layers and pass the appropriate URI to the constructor for each.

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               var trailheadsUri = new Uri(
                   "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trailheads/FeatureServer/0"
                   );
   
               var parksLayer = new FeatureLayer(parksUri);
               var trailsLayer = new FeatureLayer(trailsUri);
               var trailheadsLayer = new FeatureLayer(trailheadsUri);
   

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2. Add the feature layers to the map. Data layers are displayed in the order in which they are added. Polygon layers should be added before layers with lines or points if there's a chance the polygon symbols will obscure features beneath.

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               var parksLayer = new FeatureLayer(parksUri);
               var trailsLayer = new FeatureLayer(trailsUri);
               var trailheadsLayer = new FeatureLayer(trailheadsUri);
   
               map.OperationalLayers.Add(parksLayer);
               map.OperationalLayers.Add(trailsLayer);
               map.OperationalLayers.Add(trailheadsLayer);
   

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3. Click Debug > Start Debugging (or press <F5> on the keyboard) to run the app. If your app uses user authentication, enter your ArcGIS Online credentials when prompted.

You should see point, line, and polygon features (representing trailheads, trails, and parks) draw on the map for an area in the Santa Monica Mountains.

Option 2: Download the solution

1. Click the Download solution link in the right-hand panel of the page.

2. Unzip the file to a location on your machine.

3. Open the .sln file in Visual Studio.

Since the downloaded solution does not contain authentication credentials, you must first set up authentication to create credentials, and then add the developer credentials to the solution.

Set up authentication

To access the secure ArcGIS location services used in this tutorial, you must implement API key authentication or user authentication using an ArcGIS Location Platform or an ArcGIS Online account.

Set developer credentials in the solution

To allow your app users to access ArcGIS location services, use the developer credentials that you created in the Set up authentication step to authenticate requests for resources.

Run the solution

Click Debug > Start Debugging (or press <F5> on the keyboard) to run the app. If your app uses user authentication, enter your ArcGIS Online credentials when prompted.

You should see point, line, and polygon features (representing trailheads, trails, and parks) draw on the map for an area in the Santa Monica Mountains.