Add a point, line, and polygon

Learn how to display point, line, and polygon graphics in a map.

You typically use graphics to display geographic data that is not connected to a database and that is not persisted, like highlighting a route between two locations, displaying a search buffer around a selected point, or showing the location of map coordinates entered by the user. Graphics are composed of a geometry, symbol, and attributes.

In this tutorial, you display points, lines, and polygons on a map as graphics.

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 service.

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 display point, line, and polygon graphics in the map view.

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 AddPointLineAndPolygon 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.
- Click Apply in the Rename: DisplayAMap window that appears in the upper-right of the code window. This will rename the namespace throughout your project.
Build the project.
- Choose Build > Build solution (or press <F6>).

Add a graphics overlay

A graphics overlay is a container for graphics. It is used with a map view to display graphics on a map. You can add more than one graphics overlay to a map view. Graphics overlays are displayed on top of all the other layers.

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.

Add additional required using statements to your MapViewModel class. Esri.ArcGISRuntime.UI namespace contains the Graphic class and Esri.ArcGISRuntime.Symbology namespace contains the classes that define the symbols for displaying them.

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using System;
using System.Collections.Generic;
using System.Text;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using System.ComponentModel;
using System.Runtime.CompilerServices;

using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.UI;
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In the view model, create a new property named GraphicsOverlays. This will be a collection of GraphicsOverlay that will store point, line, and polygon graphics.

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        private Map? _map;
        public Map? Map
        {
            get { return _map; }
            set
            {
                _map = value;
                OnPropertyChanged();
            }
        }

        private GraphicsOverlayCollection? _graphicsOverlays;
        public GraphicsOverlayCollection? GraphicsOverlays
        {
            get { return _graphicsOverlays; }
            set
            {
                _graphicsOverlays = value;
                OnPropertyChanged();
            }
        }
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Add a new method in the view model named CreateGraphicsOverlays. Add code to create a new GraphicsOverlay and assign it to the GraphicsOverlays property.

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        private void SetupMap()
        {
            // Create a new map with a 'topographic vector' basemap.
            var 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;
        }

        private void CreateGraphicsOverlays()
        {
            // Create a new graphics overlay to contain a variety of graphics.
            var malibuGraphicsOverlay = new GraphicsOverlay();

            // Add the overlay to a graphics overlay collection.
            GraphicsOverlayCollection overlays = new GraphicsOverlayCollection
            {
                malibuGraphicsOverlay
            };

            // Set the view model's "GraphicsOverlays" property (will be consumed by the map view).
            this.GraphicsOverlays = overlays;

        }
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In the MapViewModel constructor, add a call to the CreateGraphicsOverlays function.

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        public MapViewModel()
        {
            SetupMap();

            CreateGraphicsOverlays();

        }
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In the Visual Studio > Solution Explorer, double-click MainWindow.xaml to open the file.
Use data binding to bind the GraphicsOverlays property of the MapViewModel to the MapView control.

Data binding and the Model-View-ViewModel (MVVM) design pattern allow you to separate the logic in your app (the view model) from the presentation layer (the view). Graphics can be added and removed from the graphics overlays in the view model and those changes appear in the map view through data binding.
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```
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        <esri:MapView x:Name="MainMapView"
                          Map="{Binding Map, Source={StaticResource MapViewModel}}"
                          GraphicsOverlays="{Binding GraphicsOverlays, Source={StaticResource MapViewModel}}" />
```
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Add a point graphic

A point graphic is created using a map point and a marker symbol. A map point is defined with x and y coordinates and a spatial reference. For latitude and longitude coordinates, the spatial reference is WGS84.

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

In the CreateGraphicsOverlays function, add code to create a MapPoint and a SimpleMarkerSymbol. To create the MapPoint, provide longitude (x) and latitude (y) coordinates, and a SpatialReference. Use the SpatialReferences.Wgs84 static property.

Point graphics support a number of symbol types such as SimpleMarkerSymbol, PictureMarkerSymbol and TextSymbol. Learn more about Symbol in the API Reference documentation.

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            // Set the view model's "GraphicsOverlays" property (will be consumed by the map view).
            this.GraphicsOverlays = overlays;

            // Create a point geometry.
            var dumeBeachPoint = new MapPoint(-118.8066, 34.0006, SpatialReferences.Wgs84);

            // Create a symbol to define how the point is displayed.
            var pointSymbol = new SimpleMarkerSymbol
            {
                Style = SimpleMarkerSymbolStyle.Circle,
                Color = System.Drawing.Color.Orange,
                Size = 10.0
            };

            // Add an outline to the symbol.
            pointSymbol.Outline = new SimpleLineSymbol
            {
                Style = SimpleLineSymbolStyle.Solid,
                Color = System.Drawing.Color.Blue,
                Width = 2.0
            };
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Create a Graphic with the point and pointSymbol. Display the Graphic by adding it to the GraphicsOverlay.Graphics collection.

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            // Add an outline to the symbol.
            pointSymbol.Outline = new SimpleLineSymbol
            {
                Style = SimpleLineSymbolStyle.Solid,
                Color = System.Drawing.Color.Blue,
                Width = 2.0
            };

            // Create a point graphic with the geometry and symbol.
            var pointGraphic = new Graphic(dumeBeachPoint, pointSymbol);

            // Add the point graphic to graphics overlay.
            malibuGraphicsOverlay.Graphics.Add(pointGraphic);
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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 will see a point graphic displayed on the map in Point Dume State Beach.

Add a line graphic

A line graphic is created using a polyline and a line symbol. A polyline is defined as a sequence of points.

Polylines have one or more distinct parts, and each part is a sequence of points. For a continuous line, you can use the Polyline constructor to create a polyline with just one part. To create a polyline with more than one part, use a PolylineBuilder.

Create a Polyline and a SimpleLineSymbol. To create the Polyline, provide an array of MapPoint as the constructor argument.

Line graphics support a number of symbol types such as SimpleLineSymbol and TextSymbol. Learn more about Symbol in the API Reference documentation.

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            // Add the point graphic to graphics overlay.
            malibuGraphicsOverlay.Graphics.Add(pointGraphic);

            // Create a list of points that define a polyline.
            List<MapPoint> linePoints = new List<MapPoint>
            {
                new MapPoint(-118.8215, 34.0140, SpatialReferences.Wgs84),
                new MapPoint(-118.8149, 34.0081, SpatialReferences.Wgs84),
                new MapPoint(-118.8089, 34.0017, SpatialReferences.Wgs84)
            };

            // Create polyline geometry from the points.
            var westwardBeachPolyline = new Polyline(linePoints);

            // Create a symbol for displaying the line.
            var polylineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Blue, 3.0);
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Create a Graphic with the polyline and polylineSymbol. Display the Graphic by adding it to the GraphicsOverlay.Graphics collection.

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            // Create a symbol for displaying the line.
            var polylineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Blue, 3.0);

            // Create a polyline graphic with geometry and symbol.
            var polylineGraphic = new Graphic(westwardBeachPolyline, polylineSymbol);

            // Add polyline to graphics overlay.
            malibuGraphicsOverlay.Graphics.Add(polylineGraphic);
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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 will now see a line graphic displayed on the map along Westward Beach, as well as the point you added previously.

Add a polygon graphic

A polygon graphic is created using a polygon and a fill symbol. A polygon is defined as a sequence of points that describe a closed boundary.

Polygons have one or more distinct parts. Each part is a sequence of points that comprise a closed boundary. For a single area with no openings, you can use the Polygon constructor to create a polygon made of just one part. To create a polygon that consists of more than one part, use a PolygonBuilder.

Create a Polygon and a SimpleFillSymbol. To create the Polygon, provide an array of MapPoints.

Polygon graphics support a number of symbol types such as SimpleFillSymbol, PictureFillSymbol, SimpleMarkerSymbol and TextSymbol. Learn more about Symbol in the API Reference documentation.

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            // Add polyline to graphics overlay.
            malibuGraphicsOverlay.Graphics.Add(polylineGraphic);

            // Create a list of points that define a polygon boundary.
            List<MapPoint> polygonPoints = new List<MapPoint>
            {
                new MapPoint(-118.8190, 34.0138, SpatialReferences.Wgs84),
                new MapPoint(-118.8068, 34.0216, SpatialReferences.Wgs84),
                new MapPoint(-118.7914, 34.0164, SpatialReferences.Wgs84),
                new MapPoint(-118.7960, 34.0086, SpatialReferences.Wgs84),
                new MapPoint(-118.8086, 34.0035, SpatialReferences.Wgs84)
            };

            // Create polygon geometry.
            var mahouRivieraPolygon = new Polygon(polygonPoints);

            // Create a fill symbol to display the polygon.
            var polygonSymbolOutline = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Blue, 2.0);
            var polygonFillSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle.Solid, System.Drawing.Color.Orange, polygonSymbolOutline);
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Create a Graphic with the polygon and the fill symbol. Display the Graphic by adding it to the GraphicsOverlay.Graphics collection.

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            // Create a fill symbol to display the polygon.
            var polygonSymbolOutline = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Blue, 2.0);
            var polygonFillSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle.Solid, System.Drawing.Color.Orange, polygonSymbolOutline);

            // Create a polygon graphic with the geometry and fill symbol.
            var polygonGraphic = new Graphic(mahouRivieraPolygon, polygonFillSymbol);

            // Add the polygon graphic to the graphics overlay.
            malibuGraphicsOverlay.Graphics.Add(polygonGraphic);
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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 will see your previously added point and line graphics, and a new polygon graphic around Mahou Riviera 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 services used in this tutorial, you must implement API key authentication or user authentication using an ArcGIS Location Platform or an ArcGIS Online account.

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

API key authentication

Users are not required to sign in.
Requires creating an API key credential with the correct privileges.
API keys 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 authentication

Users are required to sign in with an ArcGIS account.
User accounts must have privilege to access the ArcGIS services used in application.
Requires creating OAuth credentials.
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.

Create a new API key access token with privileges 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
  - Location services > Basemaps
Copy and paste the API key access token into a safe location. It will be used in a later step.

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

Complete the Create OAuth credentials for user authentication tutorial.
Copy and paste the ClientID and RedirectURL into a safe location. They will be used in a later step.

All users that access this application need account privileges to access the basemap styles service.

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.

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.SetChallengeHandler();

        }

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.SetChallengeHandler();

        }

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
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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.SetChallengeHandler();

        }

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 will see point, line, and polygon graphics displayed on the map around the Mahou Riviera area near Malibu, California.

What's next?

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