Add layers to a map | ArcGIS for Developers

ArcGIS DevLabs NET Maps & Layers

Overview

You will learn: how to add feature layers to a 2D map.

With ArcGIS Runtime SDK for .NET, it's easy to create a mapping app that displays a basemap and one or more layers. ArcGIS Online hosts several basemaps (in both image and vector tile format) that you can use in your map (2D) or scene (3D). Feature layers allow you to add datasets hosted online (with ArcGIS Online or other ArcGIS servers) or stored locally (in a runtime geodatabase, for example). The data returned and the symbology used can be customized for a feature layer.

In this lab you will create a new map with an imagery basemap, add a feature layer to it, and display the map in your app.

Steps

Create a new ArcGIS Runtime App Visual Studio Project

Start Visual Studio.

Visual Studio 2015 is recommended. Please check system requirements for more information.
Choose File > New > Project and select the ArcGIS Runtime App template for your chosen platform.

You need to install the ArcGIS Runtime SDK for .NET Visual Studio Extension to add these templates to Visual Studio. See the Install topic in the developers guide for more information.

Create a new map with an imagery basemap

Open the MapViewModel.cs code file in your project. Find the definition for the Map property in the class. Notice that the default map is currently set to display the streets raster tile basemap.

The ArcGIS Runtime App templates use the Model-View-ViewModel (MVVM) pattern. The Map property in the MapViewModel class is bound to the Map property of the MapView in the UI.
Add the following function to the MapViewModel class:
```
private async void CreateNewMap()
{

}
```
Add code to create a new Map with an imagery basemap.

There are several static methods on the Basemap class that allow you to easily create a basemap for a new Map: CreateStreets, CreateTopographic, CreateImagery, and so on.
```
Map newMap = new Map(Basemap.CreateImageryWithLabels());
```

Create a new map layer

Add code that creates a new FeatureLayer. For the layer data source, provide a URI to the Trailheads layer in the Los Angeles Trails map service.

FeatureLayer trailHeadsLayer = new FeatureLayer(new Uri("https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trailheads/FeatureServer/0"));

Load the layer asynchronously and await its completion.

A layer will load automatically when its associated Map loads. Sometimes, however, you might need information about the layer that is only available once it's loaded. In this case, you'll need the value of the feature layer's FullExtent property to define the area of the initial map display.
```
await trailHeadsLayer.LoadAsync();
```
Add the layer to the map's collection of operational layers.

Operational layers are those that the user can interact with (query, identify, select, and so on). Basemap layers, by contrast, provide a visual context over which operational layers are drawn.
```
newMap.OperationalLayers.Add(trailHeadsLayer);
```
Set the initial display area (Viewpoint) of the map to the extent of features in the trailheads layer.
```
newMap.InitialViewpoint = new Viewpoint(trailHeadsLayer.FullExtent);
```

Display the new map in your app

Set the MapViewModel.Map property with your new map.

It's important to set the Map property rather than the private _map variable. Setting the Map property includes a call to OnPropertyChanged that will let the View know the map has been updated.
```
Map = newMap;
```
Call your CreateNewMap function from the MapViewModel constructor.
```
public MapViewModel()
{
   CreateNewMap();
}
```
Run your app to test your code. When the app opens, you should see an imagery map of Los Angeles appear with trailhead points displayed on top.

Congratulations, you're done!

Check out and compare with our completed solution project.

Challenge

Explore basemaps

Look at the available static methods on the Basemap class for creating basemaps for your Map. Modify your code to display a different basemap. For example:

Map newMap = new Map(Basemap.CreateNationalGeographic());

Add additional feature layers

Visit ArcGIS Online and find additional interesting park datasets to load into the app. Here are a couple suggestions:

Trails (lines): https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trails/FeatureServer/0
Parks (polygons): https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Parks_and_Open_Space/FeatureServer/0

Filter features in the trailheads layer

Sometimes you want your layer to show a subset of the data from a service. A definition expression lets you define attribute criteria that restrict the features for a layer. Consult the service info for the Trailheads data source and construct an expression for the layer's DefinitionExpression property that will show only trailheads without parking.