Add a feature layer from a portal item

Before starting this tutorial:

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

2. Your system meets the system requirements.

3. The ArcGIS Maps SDK for Qt, version 200.7.0 or later is installed.

4. The Qt 6.8.2 software development framework is installed.

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 Qt Creator project

1. Open the project you created by completing the Display a map tutorial.
2. Continue with the following instructions to use an ArcGIS portal item to access and display a feature layer in a map.

Include header files

Your app needs the Portal and PortalItem classes to load an item hosted on ArcGIS Online and display it as a FeatureLayer in the map.

1. In the project, open the Sources folder and open the Display_a_map.cpp file. Add the following four include statements.

   Display-a-map.cpp

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   #include "Display_a_map.h"
   #include "Map.h"
   #include "MapTypes.h"
   #include "MapQuickView.h"
   #include "Point.h"
   #include "Viewpoint.h"
   #include "SpatialReference.h"
   #include <QFuture>
   
   #include "Portal.h"
   #include "PortalItem.h"
   #include "FeatureLayer.h"
   #include "LayerListModel.h"
   

Add the trailheads feature layer to the map

You will connect to ArcGIS Online and access a hosted item (trailheads layer) using its item ID. You can then create a FeatureLayer to display the PortalItem in the map.

1. Create a Portal instance using the default constructor.

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     const Point center(-118.80543, 34.02700, SpatialReference::wgs84());
     const Viewpoint viewpoint(center, 100000.0);
     m_mapView->setViewpointAsync(viewpoint);
   
     Portal* portal = new Portal(this);
   

2. Create a PortalItem that references the trailheads item ID on the Portal.

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     Portal* portal = new Portal(this);
   
     const QString itemId("2e4b3df6ba4b44969a3bc9827de746b3");
     PortalItem* portalItem = new PortalItem(portal, itemId, this);
   

3. Create a FeatureLayer, using the PortalItem and referencing a serviceLayerId of 0 (zero). Then append this layer to the map's data layers (operational layers). Save the file.

   Display-a-map.cpp

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     const QString itemId("2e4b3df6ba4b44969a3bc9827de746b3");
     PortalItem* portalItem = new PortalItem(portal, itemId, this);
   
     FeatureLayer* trailheadsLayer = new FeatureLayer(portalItem, 0, this);
     m_map->operationalLayers()->append(trailheadsLayer);
   

   Expand

   Press Ctrl + R to run the app.

Your app should display a map with the trailheads centered on the Santa Monica Mountains. Double-click, drag, and scroll the mouse wheel over the map view to explore the map.

Option 2: Download the solution

1. Click the Download solution link under Solution and unzip the file to a location on your machine.

2. Open the project in Qt Creator.

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

Set up authentication

To access the secure ArcGIS location services used in this tutorial, you must implement API key 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

Press Ctrl + R to run the app.

Your app should display a map with the trailheads centered on the Santa Monica Mountains. Double-click, drag, and scroll the mouse wheel over the map view to explore the map.