Display a map

Learn how to create and display a map with a basemap layer.

A map contains layers of geographic data. A map contains a basemap layer and, optionally, one or more data layers. You can display a specific area of a map by using a map view and setting the location and zoom level.

In this tutorial, you create and display a map of the Santa Monica Mountains in California using the topographic basemap layer.

The map and code will be used as the starting point for other 2D tutorials.

Prerequisites

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 200.5.0 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_a_map. 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 6.5.6 MSVC2019 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.

Get an access token

You need an access token to use the location services used in this tutorial.

1. Go to the Create an API key tutorial to obtain an access token.

2. Ensure that the following privilege is enabled: Location services > Basemaps > Basemap styles service.

3. Copy the access token as it will be used in the next step.

To learn more about other ways to get an access token, go to Types of authentication.

Set your API key

In the Projects window, in the Sources folder, open the main.cpp file. Modify the code to set the API key. Paste the access token between the double quotes. Save and close the file.

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    // 2. API key authentication: Get a long-lived access token that gives your application access to
    // ArcGIS location services. Go to the tutorial at https://links.esri.com/create-an-api-key.
    // Copy the API Key access token.

    const QString accessToken = QString("");

Add a map

Use the map view to display a map centered on the Santa Monica Mountains in California. The map will contain a layer built from the ArcGISTopographic BasemapStyle.

1. In the Projects window, open the Headers folder. Double-click the file display_a_map.h to open it.

2. Add the declaration void setupViewpoint(); under private:. Then save and close the file.

   Display_a_map.h

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

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3. In the Projects window, open the Sources folder. Open the display_a_map.cpp file.

4. Add the following #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>
   

Create the view point

1. Add code to implement the setupViewpoint method. This method creates a center Point based on a SpatialReference along with longitude and latitude. It also creates a Viewpoint based on center and sets scale. Lastly, it asynchronously sets the initial Map viewpoint.

   The center Point and scale value keep the initial Viewpoint centered and focused on the Santa Monica Mountains. The scale value sets the level of detail to focus on the area of interest.

   The spatial reference created above is set to use World Geodetic System 1984 (WGS84), the spatial reference commonly used for GPS, and it has the well known id 4326. To learn more, see Spatial References in the ArcGIS Maps SDK for Qt Guide.

   Display_a_map.cpp

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   MapQuickView* Display_a_map::mapView() const
   {
       return m_mapView;
   }
   
   void Display_a_map::setupViewpoint()
   {
   
       const Point center(-118.80543, 34.02700, SpatialReference::wgs84());
       const Viewpoint viewpoint(center, 100000.0);
       m_mapView->setViewpointAsync(viewpoint);
   
   }
   
   

   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. You should not modify it.

2. Add the following line of code to call setupViewpoint.

   Display_a_map.cpp

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

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3. Press Ctrl + R to run the app.

You should see a map with the topographic basemap layer centered on the Santa Monica Mountains in California. Zoom in and out, and drag the map view to explore the map.

What's next?

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

• Add a point, line, and polygon
• Add a feature layer
• Search for an address
• Find a route and directions
• Display a web map
• Display a scene