Add a feature layer from a portal item

Learn how to use an ArcGIS portal item to access and display a feature layer in a map.

You can host a variety of geographic data and other resources using ArcGIS Online. These portal items can also define how the data is presented. A web map or web scene, for example, not only defines the layers for a map or scene, but also how layers are symbolized, the minimum and/or maximum scales at which they display, and several other properties. Likewise, a hosted feature layer contains the data for the layer and also defines the symbols and other display properties for how it is presented. When you add a map, scene, or layer from a portal item to your ArcGIS Runtime app, everything that has been saved with the item is applied in your app. Adding portal items to your ArcGIS Runtime app rather than creating them programmatically saves you from writing a lot of code, and can provide consistency across apps that use the same data.

In this tutorial, you will add a hosted feature layer to display trailheads in the Santa Monica Mountains of Southern California. The hosted layer defines the trailhead locations (points) as well as the symbols used to display them.

Prerequisites

In your browser, go to the Trailheads Styled layer on ArcGIS Online and find the item ID at the end of the URL. It should be 2e4b3df6ba4b44969a3bc9827de746b3.

Steps

1. Open the ViewController.swift file, update the setupMap() method to create an AGSPortal object and an AGSPortalItem object referencing the feature layer.

   More info

   Each portal item has a unique itemID, identified from its URL on ArcGIS Online.

   The feature layer referenced with this portal item contains trailheads in and around the Santa Monica Mountains.

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        mapView.map = AGSMap(basemapType: .navigationVector, latitude: 34.09042, longitude: -118.71511, levelOfDetail: 10)
   
        // *** ADD ***
        let portal = AGSPortal(url: URL(string: "https://www.arcgis.com")!, loginRequired: false)
        let item = AGSPortalItem(portal: portal, itemID: "2e4b3df6ba4b44969a3bc9827de746b3")

2. Create an AGSFeatureLayer object from the portal item and a layer ID. Add the layer to the map's operational layers.

   More info

   A layer ID is required because a portal item may have more than one layer. For instance, when a feature service has 3 layers - trailheads (points), trails (polylines) and trail areas (polygons), the corresponding portal item would contain all three layers.

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        let item = AGSPortalItem(portal: portal, itemID: "2e4b3df6ba4b44969a3bc9827de746b3")
   
        // *** ADD ***
        let layer = AGSFeatureLayer(item: item, layerID: 0)
        mapView.map!.operationalLayers.add(layer)

3. Press Command-R to run the app in the iOS Simulator.

   More info

   Other ways to run the project in Xcode:

   • In Xcode's app menu, select Product > Run.
   • Pressing the Run button at the top-left of the Xcode project window.

Your app should display a map with the trailheads centered on the Santa Monica Mountains. Compare your solution with our completed solution project.

What's next?

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

• Display a web map
• Display a web scene