Add a feature layer | ArcGIS Maps SDK for .NET

Learn how to use a URL to access and display a feature layerA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more in a map.A map is a collection of layers that are displayed in 2D. It is typically composed of a basemap layer and data layers.Learn more

A mapA map is a collection of layers that are displayed in 2D. It is typically composed of a basemap layer and data layers.Learn more contains layersA layer is a reference to a collection of geographic data that is used to access and display data. The data for layers are typically provided by the basemap layer service and data services.Learn more of geographic data. A map contains a basemap layerA basemap layer is the layer in a map or scene that displays basemap data. The data source for a basemap layer is typically a basemap service.Learn more and, optionally, one or more data layersA data layer is a layer that references geographic data from a file or a service and is used to visualize the data in a map or scene.Learn more. This tutorial shows you how to access and display a feature layerA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more in a mapA map is a collection of layers that are displayed in 2D. It is typically composed of a basemap layer and data layers.Learn more. You access feature layers with an itemAn item, also known as a content item, is a resource stored in a portal such as a web map, hosted layer, style, script tool, file, or notebook.Learn more ID or URL. You will use URLs to access the Trailheads, Trails, and Parks and Open Spaces feature layers and display them in a map.

A feature layerA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more is a dataset in a feature serviceA feature service is a data service that provides access to spatial and non-spatial data in feature layers, feature layer views, and tables.Learn more hosted in ArcGISArcGIS is the brand name for all of the desktop, server, and developer products and technologies offered by Esri.Learn more. Each feature layer contains featuresA feature is a single record, also known as a row, that represents a real-world entity. It typically contains a geometry (point, multipoint, polyline, or polygon) and attributes but it can also contain just attributes.Learn more with a single geometryA geometry is a geometric shape, such as a point, polyline, or polygon, that contains one or more coordinates and a spatial reference.Learn more type (pointA point is a type of geometry containing a single set of x,y coordinates and a spatial reference.Learn more, lineA polyline is a type of geometry containing ordered point coordinates and a spatial reference.Learn more, or polygonA polygon is a type of geometry containing an array of rings and a spatial reference. Each ring contains an array of point coordinates, where the first and last point are the same.Learn more), and a set of attributesAttributes are fields and values for a single feature or non-spatial record. They are typically stored in a database or service such as a feature service.Learn more. You can use feature layers to store, access, and manage large amounts of geographic data for your applications.

In this tutorial, you use URLs to access and display three different feature layersA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more hosted in ArcGIS OnlineArcGIS Online is a GIS mapping, analytics, data hosting, and content management software as a service (SaaS) product. It includes applications, tools, APIs, and location services for users and developers. It is subscription-based and requires an ArcGIS Online account.Learn more:

Prerequisites

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.

Develop or download

You have two options for completing this tutorial:

Option 1: Develop the code or
Option 2: Download the completed solution

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 serviceThe ArcGIS Basemap Styles service, also referred to as the Basemap Styles service, is a location service that provides basemap styles and data for the world. It returns styles as Mapbox styles and web maps, and data as vector tiles and/or map tiles. It supports all of the styles in the ArcGIS Basemap style and Open Basemap style family. An ArcGIS Location Platform or ArcGIS Online account is required to use the service.Learn more.

Open a Visual Studio solution

Open the Visual Studio solution you created by completing the Display a map tutorial.
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.

The tutorial instructions and code use the name AddAFeatureLayer for the solution, project, and namespace. You can choose any name you like, but it should be the same for each of these.

Update the name for the solution and the project.
- In Visual Studio, in the Solution Explorer, right-click the solution name and choose Rename. Provide the new name for your solution.
- In the Solution Explorer, right-click the project name and choose Rename. Provide the new name for your project.
Rename the namespace used by classes in the project.
- In the Solution Explorer, expand the project node.
- Double-click MapViewModel.cs in the Solution Explorer to open the file.
- In the MapViewModel class, double-click the namespace name (DisplayAMap) to select it, and then right-click and choose Rename....
- Provide the new name for the namespace.
- Hit Enter to confirm the new name. This will rename the namespace throughout your project.
Build the project.
- Choose Build > Build solution (or press <F6>).

Create URIs to reference feature service data

To display three new data layersA data layer is a layer that references geographic data from a file or a service and is used to visualize the data in a map or scene.Learn more (also known as operational layers) on top of the current basemap, you will create FeatureLayers using URIs to reference datasets hosted in ArcGIS OnlineArcGIS Online is a GIS mapping, analytics, data hosting, and content management software as a service (SaaS) product. It includes applications, tools, APIs, and location services for users and developers. It is subscription-based and requires an ArcGIS Online account.Learn more.

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.

The ArcGIS REST Services Directory page provides information such as the geometryA geometry is a geometric shape, such as a point, polyline, or polygon, that contains one or more coordinates and a spatial reference.Learn more type, the geographic extentAn extent is a bounding rectangle with points that delineate an area for a map or scene.Learn more, the minimum and maximum scaleZoom level is a value that sets the scale for a map view or a scene view.Learn more at which features are visible, and the attributesAttributes are fields and values for a single feature or non-spatial record. They are typically stored in a database or service such as a feature service.Learn more (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.
In the Visual Studio > Solution Explorer, double-click MapViewModel.cs to open the file.

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.

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"
                );
Expand

Create feature layers to display the hosted data

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

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);
Expand

Add the feature layers to the map. Data layersA data layer is a layer that references geographic data from a file or a service and is used to visualize the data in a map or scene.Learn more are displayed in the order in which they are added. PolygonA polygon is a type of geometry containing an array of rings and a spatial reference. Each ring contains an array of point coordinates, where the first and last point are the same.Learn more layers should be added before layers with linesA polyline is a type of geometry containing ordered point coordinates and a spatial reference.Learn more or pointsA point is a type of geometry containing a single set of x,y coordinates and a spatial reference.Learn more 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);
```
Expand
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.

Alternatively, you can download the tutorial solution, as follows.

Option 2: Download the solution

Click the Download solution link in the right-hand panel of the page.
Unzip the file to a location on your machine.
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 servicesArcGIS Location Services, also referred to as Location Services, are services hosted by Esri that provide geospatial functionality for developing mapping applications. They include the ArcGIS Basemap Styles service, ArcGIS Static Basemap Tiles service, ArcGIS Places service, ArcGIS Geocoding service, ArcGIS Routing service, ArcGIS GeoEnrichment service, and ArcGIS Elevation service. An ArcGIS Location Platform or ArcGIS Online account is required to use the services.Learn more used in this tutorial, you must implement API key authenticationAPI key authentication is a type of authentication that uses an API key to authenticate requests to ArcGIS services and secure portal items.Learn more or user authenticationUser authentication is a type of authentication that allows users with an ArcGIS account to sign into an application and allow it to access ArcGIS content, services, and resources on their behalf. The typical authorization protocol used is OAuth2.0.Learn more using an ArcGIS Location PlatformAn ArcGIS Location Platform account, formerly known as an ArcGIS Developer account, is an identity associated with an ArcGIS Location Platform subscription.Learn more or an ArcGIS OnlineAn ArcGIS Online account, also known as an ArcGIS Organization account, is an identity associated with an ArcGIS Online subscription. It can be used to access ArcGIS tools and develop applications with ArcGIS location services for an organization.Learn more account.

You can implement API key authentication or user authentication in this tutorial. Compare the differences below:

API key authenticationAPI key authentication is a type of authentication that uses an API key to authenticate requests to ArcGIS services and secure portal items.Learn more

Users are not required to sign in.
Requires creating an API key credentialAPI key credentials are an item that contains the parameters used to create and manage long-lived access tokens for API key authentication. They are a type of developer credential.Learn more with the correct privileges.
API keysAn API key is a long-lived access token created using API key credentials. They are valid for up to one year and are typically embedded directly into client applications.Learn more are long-lived access tokens.
Service usage is billed to the API key owner/developer.
Simplest authentication method to implement.
Recommended approach for new ArcGIS developers.

Learn more in API key authentication.

User authenticationUser authentication is a type of authentication that allows users with an ArcGIS account to sign into an application and allow it to access ArcGIS content, services, and resources on their behalf. The typical authorization protocol used is OAuth2.0.Learn more

Users are required to sign in with an ArcGIS accountAn ArcGIS account is an identity with a user type and set of privileges that can access specific ArcGIS products, tools, APIs, services, and resources. The main account types that can be used for development are an ArcGIS Location Platform account, ArcGIS Online account, and ArcGIS Enterprise account. ArcGIS Location Platform and ArcGIS Online accounts are also associated with a subscription.Learn more.
User accounts must have privilegePrivileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS.Learn more to access the ArcGIS servicesA service, also known as an ArcGIS service, is software that supports an ArcGIS REST API and provides geospatial functionality or data. A service can be hosted by Esri or in ArcGIS Enterprise.Learn more used in application.
Requires creating OAuth credentialsOAuth credentials are an item that contains parameters required to implement user authentication or app authentication, including a client_id, client_secret, and redirect URIs. They are a type of developer credential.Learn more.
Application uses a redirect URL and client ID.
Service usage is billed to the organization of the user signed into the application.

Learn more in User authentication.

To complete this tutorial, click on the tab in the switcher below for your authentication type of choice, either API key authentication or User authentication.

Create a new API key access tokenAn access token is an authorization string that provides access to secure ArcGIS content, data, and services. Its capabilities are determined by the privileges it supports. It is obtained by implementing API key authentication, User authentication, or App authentication.Learn more with privilegesPrivileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS.Learn more to access the secure resources used in this tutorial.

Complete the Create an API key tutorial and create an API key with the following privilege(s)Privileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS.Learn more:
- Privileges
  - Location services > Basemaps
Copy and paste the API key access token into a safe location. It will be used in a later step.

Create new OAuth credentials to access the secure resources used in this tutorial.

Complete the Create OAuth credentials for user authentication tutorial to obtain a Client ID and Redirect URL.

A Client ID uniquely identifies your app on the authenticating server. If the server cannot find an app with the provided Client ID, it will not proceed with authentication.
The Redirect URL (also referred to as a callback url) is used to identify a response from the authenticating server when the system returns control back to your app after an OAuth login. Since it does not necessarily represent a valid endpoint that a user could navigate to, the redirect URL can use a custom scheme, such as my-app://auth. It is important to make sure the redirect URL used in your app's code matches a redirect URL configured on the authenticating server.
Copy and paste the Client ID and Redirect URL into a safe location. They will be used in a later step.

All users that access this application need account privilegesPrivileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS.Learn more to access the ArcGIS Basemap Styles serviceThe ArcGIS Basemap Styles service, also referred to as the Basemap Styles service, is a location service that provides basemap styles and data for the world. It returns styles as Mapbox styles and web maps, and data as vector tiles and/or map tiles. It supports all of the styles in the ArcGIS Basemap style and Open Basemap style family. An ArcGIS Location Platform or ArcGIS Online account is required to use the service.Learn more.

Set developer credentials in the solution

To allow your app users to access ArcGIS location servicesArcGIS Location Services, also referred to as Location Services, are services hosted by Esri that provide geospatial functionality for developing mapping applications. They include the ArcGIS Basemap Styles service, ArcGIS Static Basemap Tiles service, ArcGIS Places service, ArcGIS Geocoding service, ArcGIS Routing service, ArcGIS GeoEnrichment service, and ArcGIS Elevation service. An ArcGIS Location Platform or ArcGIS Online account is required to use the services.Learn more, use the developer credentials that you created in the Set up authentication step to authenticate requests for resources.

In Visual Studio, in the Solution Explorer, click App.xaml.cs to open the file.

Set the ArcGISEnvironment.ApiKey property with your API key access token.

App.xaml.cs
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        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);

            // Set the access token for ArcGIS Maps SDK for .NET.
            Esri.ArcGISRuntime.ArcGISRuntimeEnvironment.ApiKey = "YOUR_ACCESS_TOKEN";

            // Call a function to set up the AuthenticationManager for OAuth.
            UserAuth.ArcGISLoginPrompt.RegisterOAuthConfig();

        }

Remove the code that sets up user authentication.

App.xaml.cs
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        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);

            // Set the access token for ArcGIS Maps SDK for .NET.
            Esri.ArcGISRuntime.ArcGISRuntimeEnvironment.ApiKey = "YOUR_ACCESS_TOKEN";

            // Call a function to set up the AuthenticationManager for OAuth.
            UserAuth.ArcGISLoginPrompt.RegisterOAuthConfig();

        }

Best Practice: The access token is stored directly in the code as a convenience for this tutorial. Do not store credentials directly in source code in a production environment.

From the Visual Studio Solution explorer window, open the ArcGISLoginPrompt.cs file.

Set your values for the client ID (OAuthClientID) and the redirect URL (OAuthRedirectUrl). These are the user authentication settings you created in the Set up authentication step.

ArcGISLoginPrompt.cs
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    internal static class ArcGISLoginPrompt
    {
        private const string ArcGISOnlineUrl = "https://www.arcgis.com/sharing/rest";
        // Specify the Client ID and Redirect URL to use with OAuth authentication.
        // See the instructions here for creating OAuth app settings:
        // https://developers.arcgis.com/documentation/security-and-authentication/user-authentication/tutorials/create-oauth-credentials-user-auth/

        private const string AppClientId = "YOUR_CLIENT_ID";
        private const string OAuthRedirectUrl = "YOUR_REDIRECT_URL";

In Visual Studio, in the Solution Explorer, click App.xaml.cs to open the file.

Remove the line of code that sets an API key access token.

App.xaml.cs
Use dark colors for code blocks
        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);

            // Set the access token for ArcGIS Maps SDK for .NET.
            Esri.ArcGISRuntime.ArcGISRuntimeEnvironment.ApiKey = "YOUR_ACCESS_TOKEN";

            // Call a function to set up the AuthenticationManager for OAuth.
            UserAuth.ArcGISLoginPrompt.RegisterOAuthConfig();

        }

Best Practice: The OAuth credentials are stored directly in the code as a convenience for this tutorial. Do not store credentials directly in source code in a production environment.

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.

What's next?

Learn how to use additional API features, ArcGIS location services, and ArcGIS tools in these tutorials: