Display device location

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

Create a new ArcGIS Maps Qt Creator Project

1. Start Qt Creator.

2. In the top menu bar, click File > New Project.

3. In the New Project dialog, in the left frame, under Projects, select ArcGIS. Then select the ArcGIS Maps 200.7.0 Qt Quick C++ app project template (or a later version) and click Choose. This will launch the template wizard.

4. In the Project Location template, name your project Display_device_location. You can specify your own "create in" location for where the project will be created or leave the default. Click Next.

5. In the Define Build System template, select qmake for your build system. Click Next.

6. In the Define Project Details template, give this app a description or leave as is. Leave the 3D project box unchecked. At the ArcGIS Online Basemap dropdown menu, select Topographic. There is no need to supply an API Key (also called an access token) at this time, you can leave it blank. We will discuss this more in the next section. Click Next.

7. In the Kit Selection template, check on the kit you previously set up when you installed Qt (Desktop Qt 6.8.2 MSVC2022 64bit or higher required). Click Next.

8. In the Project Management template, the option to Add as a subproject to root project is only available if you have already created a root project. If you have a version control system set up, you can select it in the dropdown but it is not needed to complete this tutorial. Click Finish to complete the template wizard.

Set developer credentials

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.

Declare the new method in the header file

1. In the Projects window, open the Headers folder. Double-click the file display_device_location.h to open it. Add the new method declaration under private:. Then save and close the file.

   Display_device_location.h

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   private:
       Esri::ArcGISRuntime::MapQuickView* mapView() const;
       void setMapView(Esri::ArcGISRuntime::MapQuickView* mapView);
   
       void startLocation();
   

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Include header files in the source code

To create this app you will need to include additional class header files from the ArcGIS Maps Qt C++ API.

1. In the Projects window, open the Sources folder. Open the display_device_location.cpp file and add the following include statements.

   Display_device_location.cpp

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   #include "Display_device_location.h"
   
   #include "Map.h"
   #include "MapTypes.h"
   #include "MapQuickView.h"
   
   #include "LocationDisplay.h"
   #include "MapViewTypes.h"
   

Show the current location

Each map view has its own instance of a LocationDisplay for showing the current location (point) of the device. The location is displayed as an overlay in the map view.

1. Add the following method. This code enables LocationDisplay for the map view and assigns a LocationDisplayAutoPanMode that centers the map at the device location.

   Display_device_location.cpp

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   MapQuickView* Display_device_location::mapView() const
   {
       return m_mapView;
   }
   
   void Display_device_location::startLocation()
   {
       // start location display
       m_mapView->locationDisplay()->start();
       // center the location display around the device location
       m_mapView->locationDisplay()->setAutoPanMode(LocationDisplayAutoPanMode::Recenter);
   }
   

   The setMapView method appearing later in this file gets a handle to the MapView object that was declared in QML code and sets the Map on the MapView for display. This code is installed by the templates that ArcGIS provides when creating a new project in Qt.

2. Within the setMapView method, add the call to the new method.

   Display_device_location.cpp

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   // Set the view (created in QML)
   void Display_device_location::setMapView(MapQuickView* mapView)
   {
       if (!mapView || mapView == m_mapView)
       {
           return;
       }
   
       m_mapView = mapView;
       m_mapView->setMap(m_map);
   
       startLocation();
   

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3. Press Ctrl + R to run the app.

You should see your current location displayed on the map. Different location symbols are used depending on the auto pan mode and whether a location is acquired. See LocationDisplayAutoPanMode for details.

By default, a round blue symbol is used to display the device's location. The location data source tries to get the most accurate location available but depending upon signal strength, satellite positions, and other factors, the location reported could be an approximation. A semi-transparent circle around the location symbol indicates the range of accuracy. As the device moves and location updates are received, the location symbol will be repositioned on 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 add the developer credentials that you created in the Set up authentication section.

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 app

Press Ctrl + R to run the app.

You should see your current location displayed on the map. Different location symbols are used depending on the auto pan mode and whether a location is acquired. See LocationDisplayAutoPanMode for details.

By default, a round blue symbol is used to display the device's location. The location data source tries to get the most accurate location available but depending upon signal strength, satellite positions, and other factors, the location reported could be an approximation. A semi-transparent circle around the location symbol indicates the range of accuracy. As the device moves and location updates are received, the location symbol will be repositioned on the map.