Learn how to find an address or place with a search bar and the geocoding service.
Geocoding is the process of converting address or place text into a location. The geocoding service can search for an address or a place and perform reverse geocoding.
In this tutorial, you use a search bar in the user interface to access the Geocoding service and search for addresses and places.
Prerequisites
Before starting this tutorial:
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You need an ArcGIS Location Platform or ArcGIS Online account.
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Your system meets the system requirements.
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The ArcGIS Maps SDK for Qt, version 200.8.0 or later is installed.
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The Qt 6.8.2 software development framework or later is installed.
Set up authentication
To access the secure ArcGIS location services used in this tutorial, you must implement API key authentication or user authentication using an ArcGIS Location Platform or an ArcGIS Online account.
You can implement API key authentication or user authentication in this tutorial. Compare the differences below:
API key authentication
- Users are not required to sign in.
- Requires creating an API key credential with the correct privileges.
- API keys are long-lived access tokens.
- Service usage is billed to the API key owner/developer.
- Simplest authentication method to implement.
- Recommended approach for new ArcGIS developers.
Learn more in API key authentication.
User authentication
- Users are required to sign in with an ArcGIS account.
- User accounts must have privilege to access the ArcGIS services used in application.
- Requires creating OAuth credentials.
- Application uses a redirect URL and client ID.
- Service usage is billed to the organization of the user signed into the application.
Learn more in User authentication.
To complete this tutorial, click on the tab in the switcher below for your authentication type of choice, either API key authentication or User authentication.
Create a new API key access token with privileges to access the secure resources used in this tutorial.
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Complete the Create an API key tutorial and create an API key with the following privilege(s):
- Privileges
- Location services > Basemaps
- Location services > Geocoding
- Privileges
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Copy and paste the API key access token into a safe location. It will be used in a later step.
Develop or Download
You have two options for completing this tutorial:
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
- Open the project you created by completing the Display a map tutorial.
- Continue with the following instructions to add a search bar to the user interface and search for an address or place using the ArcGIS Geocoding service.
Declare classes, member variables, functions, and signals
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Double click on Headers > Display_a_map.h to open the file. Declare the classes shown.
Display_a_map.hUse dark colors for code blocks namespace Esri::ArcGISRuntime { class Map; class MapQuickView; class GraphicsOverlay; class Graphic; class LocatorTask; class GeocodeResult; class SuggestResult; class TextSymbol; -
Staying in the same file, add the following two
#includestatements as shown.Display_a_map.hUse dark colors for code blocks #include <QObject> Q_MOC_INCLUDE("MapQuickView.h") #include <QAbstractListModel> #include "GeocodeParameters.h" -
Continuing in the same file, add a
Qfor the member variable_PROPERTY suggestions.Display_a_map.hUse dark colors for code blocks class Display_a_map : public QObject { Q_OBJECT Q_PROPERTY(Esri::ArcGISRuntime::MapQuickView* mapView READ mapView WRITE setMapView NOTIFY mapViewChanged) Q_PROPERTY(QAbstractListModel* suggestions READ suggestions NOTIFY suggestionsChanged) -
Add the following public member functions with the
Qmacro to allow these to be invokable from the GUI._INVOKABLE Display_a_map.hUse dark colors for code blocks public: explicit Display_a_map(QObject* parent = nullptr); ~Display_a_map() override; Q_INVOKABLE void geocode(const QString& query); Q_INVOKABLE void clearGraphics(); Q_INVOKABLE void setSuggestions(const QString& text); -
Add two new signal declarations.
Display_a_map.hUse dark colors for code blocks signals: void mapViewChanged(); void suggestionsChanged(); void hideSuggestionView(); -
Declare the
setupprivate method.Locator Task Display_a_map.hUse dark colors for code blocks private: Esri::ArcGISRuntime::MapQuickView* mapView() const; void setMapView(Esri::ArcGISRuntime::MapQuickView* mapView); void setupViewpoint(); void setupLocatorTask(); -
Finally in the Display_a_map.h file, add the following six private member functions and variables. Then save the file.
Display_a_map.hUse dark colors for code blocks private: Esri::ArcGISRuntime::MapQuickView* mapView() const; void setMapView(Esri::ArcGISRuntime::MapQuickView* mapView); void setupViewpoint(); void setupLocatorTask(); Esri::ArcGISRuntime::Map* m_map = nullptr; Esri::ArcGISRuntime::MapQuickView* m_mapView = nullptr; void configureGraphic(); QAbstractListModel* suggestions() const; Esri::ArcGISRuntime::GraphicsOverlay* m_graphicsOverlay = nullptr; Esri::ArcGISRuntime::LocatorTask* m_locatorTask = nullptr; Esri::ArcGISRuntime::Graphic* m_graphicResultLocation = nullptr; Esri::ArcGISRuntime::Graphic* m_graphicResultText = nullptr; Esri::ArcGISRuntime::TextSymbol* m_textSymbol = nullptr; QAbstractListModel* m_suggestListModel = nullptr; Esri::ArcGISRuntime::GeocodeParameters m_geocodeParams;
Include header files to access needed classes
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In Projects, double click on Sources > Display_a_map.cpp to open the file and add the following
#includestatements.Display_a_map.cppUse dark colors for code blocks #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 "AttributeListModel.h" #include "Envelope.h" #include "GeocodeResult.h" #include "Graphic.h" #include "GraphicListModel.h" #include "GraphicsOverlay.h" #include "GraphicsOverlayListModel.h" #include "LocatorTask.h" #include "SimpleMarkerSymbol.h" #include "SimpleRenderer.h" #include "SymbolTypes.h" #include "SuggestParameters.h" #include "SuggestListModel.h" #include "TextSymbol.h" -
Continuing in the same file, include the following Qt classes.
Display_a_map.cppUse dark colors for code blocks #include "AttributeListModel.h" #include "Envelope.h" #include "GeocodeResult.h" #include "Graphic.h" #include "GraphicListModel.h" #include "GraphicsOverlay.h" #include "GraphicsOverlayListModel.h" #include "LocatorTask.h" #include "SimpleMarkerSymbol.h" #include "SimpleRenderer.h" #include "SymbolTypes.h" #include "SuggestParameters.h" #include "SuggestListModel.h" #include "TextSymbol.h" #include <QAbstractListModel> #include <QGeoPositionInfoSource> #include <QUrl> #include <QUuid>
Create a locator task with geocode parameters
Geocoding is implemented with a locator, typically created by referencing a service such as the Geocoding service or, for offline geocoding, by referencing locator data contained in a mobile package. Geocoding parameters can be used to fine-tune the results, such as setting the maximum number of results or requesting additional attributes in the results.
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Staying in the Display_a_map.cpp file, add the call to
setup. This method will be implemented next.Locator Task Display_a_map.cppUse dark colors for code blocks Display_a_map::Display_a_map(QObject* parent /* = nullptr */): QObject(parent), m_map(new Map(BasemapStyle::ArcGISTopographic, this)) { setupLocatorTask(); -
Continuing in the same file, add code to begin implementing the
setupmethod and initialize the auto-suggestion list. Within the method body, create a newLocator Task LocatorTaskbased on the Geocoding service, and set it to themmember variable. Additionally, create a_locator Task SuggestParameters, instance and initialize it with three categories as shown. Then set max results to limit for the number of returned suggestion results to 5. Finally, configureGeocodeParameters, (m_geocodeParams). Add code to set the minimum match score and the attribute names for the results to be returned. Callsuggestionsonmand assign to_locator Task m._suggest List Model Display_a_map.cppUse dark colors for code blocks Display_a_map::~Display_a_map() = default; void Display_a_map::setupLocatorTask() { const QUrl geocode_service("https://geocode-api.arcgis.com/arcgis/rest/services/World/GeocodeServer"); m_locatorTask = new LocatorTask(geocode_service, this); SuggestParameters suggestParams; const QStringList categories{"Address", "POI", "Populated Place"}; suggestParams.setCategories(categories); suggestParams.setMaxResults(5); m_locatorTask->suggestions()->setSuggestParameters(suggestParams); m_geocodeParams.setMinScore(75); m_geocodeParams.setResultAttributeNames(QStringList {"Place_addr", "Match_addr"}); m_suggestListModel = m_locatorTask->suggestions(); emit suggestionsChanged(); }A locator task is used to convert an address to a point (geocode) or vice-versa (reverse geocode). An address includes any type of information that distinguishes a place. A locator involves finding matching locations for a given address. Reverse-geocoding is the opposite and finds the closest address for a given location.
Create the auto-suggestion feature
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Staying in the Display_a_map.cpp file, towards the bottom of the file, add a new
setmethod to implement the auto-suggestion feature. This generates a list of suggested addresses based on the user's input in the GUI text field.Suggestions(const Q String& text) Display_a_map.cppUse dark colors for code blocks setupViewpoint(); emit mapViewChanged(); } void Display_a_map::setSuggestions(const QString& text) { if (!m_suggestListModel) return; SuggestListModel* suggestListModel = dynamic_cast<SuggestListModel*>(m_suggestListModel); if (!suggestListModel) return; suggestListModel->setSearchText(text); } -
Update the
setupmethod to respond to the user's mouse selection of an address from the list of suggested addresses. Inject the following code immediately after the open curly braces but before the other code in the function.Viewpoint Display_a_map.cppUse dark colors for code blocks void Display_a_map::setupViewpoint() { connect(m_mapView, &MapQuickView::mousePressed, this, [this](QMouseEvent& /* event */) { emit hideSuggestionView(); }); const Point center(-118.80543, 34.02700, SpatialReference::wgs84()); const Viewpoint viewpoint(center, 100000.0); m_mapView->setViewpointAsync(viewpoint); }
Add text and marker graphics to identify location on map
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Continuing in the Display_a_map.cpp file, towards the bottom of the file, again update the
setupmethod to add the call toViewpoint configure, which will be implemented in the next step.Graphic() Display_a_map.cppUse dark colors for code blocks void Display_a_map::setupViewpoint() { connect(m_mapView, &MapQuickView::mousePressed, this, [this](QMouseEvent& /* event */) { emit hideSuggestionView(); }); const Point center(-118.80543, 34.02700, SpatialReference::wgs84()); const Viewpoint viewpoint(center, 100000.0); m_mapView->setViewpointAsync(viewpoint); configureGraphic(); } -
Still working in the Display_a_map.cpp file, implement the
configurepublic method. Create aGraphic SimpleMarkerSymbol(blue square), initialize aGraphicand add that to aGraphicsOverlay. Then createTextSymbol, initialize aGraphicwith that, and add it to theGraphicsOverlay. Then add theGraphicsOverlaytoMapView.Display_a_map.cppUse dark colors for code blocks if (!suggestListModel) return; suggestListModel->setSearchText(text); } void Display_a_map::configureGraphic() { if (m_graphicResultLocation) return; // create graphics overlay and add to map view m_graphicsOverlay = new GraphicsOverlay(this); // set a renderer on the graphics overlay SimpleRenderer* simpleRenderer = new SimpleRenderer(this); // Create a graphic and symbol to display the result location. SimpleMarkerSymbol* simpleMarkerSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle::Square, QColor("blue"), 12.0, this); simpleRenderer->setSymbol(simpleMarkerSymbol); m_graphicResultLocation = new Graphic(this); m_graphicResultLocation->setSymbol(simpleMarkerSymbol); m_graphicsOverlay->graphics()->append(m_graphicResultLocation); // Create a graphic and symbol to display a label next to the result location m_textSymbol = new TextSymbol("", QColor("red"), 18.0, HorizontalAlignment::Center, VerticalAlignment::Bottom, this); m_graphicResultText = new Graphic(this); m_graphicResultText->setSymbol(m_textSymbol); m_graphicsOverlay->graphics()->append(m_graphicResultText); m_mapView->graphicsOverlays()->append(m_graphicsOverlay); }
Add the Geocode method
An asynchronous geocode operation is required to find and return the location candidates for a given address and geocode parameters.
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Staying in the Display_a_map.cpp file, add the
geocode(const Qmethod to geocode an address when the user clicks on that address in the auto-suggestion list. This method will invoke the geocode with parameters async method on theString& query) LocatorTask. Within the body of theifstatement, the code checks for geocoding results and verifies that the graphic exists. If both conditions are met, the result location is set as the graphic’s geometry and the attributes provided by the result are copied to the graphic. The map view display is centered on the graphic before making it visible. In the final block of code, the text symbol is set, the text graphic geometry for the geocoding result display location is set, the attributes for the text graphic is set, and graphic is made visible.Display_a_map.cppUse dark colors for code blocks m_graphicsOverlay->graphics()->append(m_graphicResultText); m_mapView->graphicsOverlays()->append(m_graphicsOverlay); } void Display_a_map::geocode(const QString& query) { m_locatorTask->geocodeWithParametersAsync(query, m_geocodeParams).then(this,[this](const QList<GeocodeResult>& geocodeResults) { if (!geocodeResults.isEmpty() && m_graphicResultLocation) { // display geocode result label and position const GeocodeResult geocodeResult = geocodeResults.at(0); m_graphicResultLocation->setGeometry(geocodeResult.displayLocation()); m_graphicResultLocation->attributes()->setAttributesMap(geocodeResult.attributes()); constexpr double scale = 8000.0; m_mapView->setViewpointCenterAsync(geocodeResult.extent().center(), scale); m_graphicResultLocation->setVisible(true); m_textSymbol->setText(geocodeResult.label()); m_graphicResultText->setGeometry(geocodeResult.displayLocation()); m_graphicResultText->attributes()->setAttributesMap(geocodeResult.attributes()); m_graphicResultLocation->setVisible(true); } }); } -
Add the
suggestionsmethod to register the value ofmas the value of the QML property_suggest List Model suggestions.Display_a_map.cppUse dark colors for code blocks m_graphicResultLocation->setVisible(true); m_textSymbol->setText(geocodeResult.label()); m_graphicResultText->setGeometry(geocodeResult.displayLocation()); m_graphicResultText->attributes()->setAttributesMap(geocodeResult.attributes()); m_graphicResultLocation->setVisible(true); } }); } QAbstractListModel* Display_a_map::suggestions() const { return m_suggestListModel; } -
Finally in the Display_a_map.cpp file, add the
clearmethod. Then save the file.Graphics Display_a_map.cppUse dark colors for code blocks QAbstractListModel* Display_a_map::suggestions() const { return m_suggestListModel; } void Display_a_map::clearGraphics() { m_graphicResultLocation->setGeometry(Point()); m_graphicResultText->setGeometry(Point()); }
Create the application GUI
The GUI will let you enter partial or full addresses into a field, see a list of matching addresses, click an address and zoom to that location, and clear the address field.
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In Projects, click on Resources > qml\qml.qrc > /qml. Then open the file Display_a_mapForm.qml
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Add the following import statement.
Display_a_mapForm.qmlUse dark colors for code blocks import QtQuick import QtQuick.Controls import Esri.Display_a_map import QtQuick.Layouts -
Change the line of code for the
Mapcomponent id from:View modeltosearch. See the yellow changed line.Display_a_mapForm.qmlUse dark colors for code blocks // Create MapQuickView here, and create its Map etc. in C++ code MapView { id: view anchors.fill: parent // set focus to enable keyboard navigation focus: true } // Declare the C++ instance that creates the map etc. and supply the view Display_a_map { id: search mapView: view } -
Add the following QML code to implement the app GUI.
Display_a_mapForm.qmlUse dark colors for code blocks // Declare the C++ instance that creates the map etc. and supply the view Display_a_map { id: search mapView: view } Rectangle { // add rectangle for gui code id: searchRect width: parent.width height: childrenRect.height property int cellHeight: 40; Column { anchors { fill: parent margins: 10 } Rectangle { color: "#f7f8fa" border { color: "#7B7C7D" } radius: 2 width: parent.width height: childrenRect.height GridLayout { width: parent.width columns: 4 TextField { id: textField Layout.margins: 5 Layout.fillWidth: true font.pixelSize: 14 placeholderText: "Type in an address" selectByMouse: true onTextChanged: { if (text.length > 0 && suggestView) suggestView.visible = true; search.setSuggestions(text); } onAccepted: { suggestView.visible = false; search.geocode(textField.text); Qt.inputMethod.hide(); } } Rectangle { Layout.margins: 5 width: height height: textField.height color: "#f7f8fa" visible: textField.length === 0 enabled: visible Button { anchors.fill: parent text: "X" font.pixelSize: 16 MouseArea { anchors.fill: parent onClicked: { textField.focus = true; suggestView.visible = !suggestView.visible; } } } } Rectangle { Layout.margins: 5 width: height color: "transparent" height: textField.height visible: textField.length !== 0 enabled: visible Button { anchors.fill: parent text: "X" font.pixelSize: 16 MouseArea { anchors.fill: parent onClicked: { textField.text = ""; search.clearGraphics(); } } } } } } //Tutorial add ListView to display suggested location results and bind it to the locator task list model. ListView { id: suggestView height: 20 * searchRect.cellHeight width: textField.width model: search.suggestions visible: false clip: true delegate: Component { Rectangle { id: rect width: textField.width height: searchRect.cellHeight color: "#f7f8fa" Text { anchors { verticalCenter: parent.verticalCenter leftMargin: 5 rightMargin: 5 } font { weight: Font.Black pixelSize: 16 } width: textField.width text: label elide: Text.ElideRight color: "black" } MouseArea { anchors.fill: parent onClicked: { textField.text = label; suggestView.visible = false; search.geocode(label); Qt.inputMethod.hide(); } } } } } } }
Set developer credentials
For the final steps of this tutorial, click the tab below that corresponds to the authentication type (API key authentication or User authentication) that you chose when you completed the Display a map tutorial.
Be sure to also provide the same authentication (API key or user authentication Client ID/Redirect URL) that you used for the Display a map tutorial.
Set the API Key
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In the project Sources folder of Qt Creator, open the main.cpp file.
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Modify the code to set the
accessusing your API key access token (highlighted in yellow).Token main.cppUse dark colors for code blocks // The following methods grant an access token: // 1. User authentication: Grants a temporary access token associated with a user's ArcGIS account. // To generate a token, a user logs in to the app with an ArcGIS account that is part of an // organization in ArcGIS Online or ArcGIS Enterprise. // 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(""); if (accessToken.isEmpty()) { qWarning() << "Use of ArcGIS location services, such as the basemap styles service, requires" << "you to authenticate with an ArcGIS account or set the API Key property."; } else { ArcGISRuntimeEnvironment::setApiKey(accessToken); } -
Save the main.cpp file.
Best Practice: The access token is stored directly in the code as a convenience for this tutorial. Do not store credentials directly in source code in a production environment.
Press Ctrl + R to run the app.
You should see a map centered on the Santa Monica Mountains in California, with an address search bar at the top. Input an address in the search bar and the app will present a list of suggested addresses (not limited to the displayed map area). Click an address to zoom to that address location.
Alternatively, you can download the tutorial solution, as follows.
Option 2: Download the solution
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Click the
Download solutionlink underSolutionand unzip the file to a location on your machine. -
Open the .pro project file 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.
For the final steps of this tutorial, click the tab below that corresponds to the authentication type (API key authentication or User authentication) that you chose when you completed the Display a map tutorial.
Be sure to also provide the same authentication (API key or user authentication Client ID/Redirect URL) that you used for the Display a map tutorial.
Set developer credentials in the solution
Set the API Key
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In the project Sources folder of Qt Creator, open the main.cpp file.
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Modify the code to set the
accessusing your API key access token (highlighted in yellow).Token main.cppUse dark colors for code blocks // The following methods grant an access token: // 1. User authentication: Grants a temporary access token associated with a user's ArcGIS account. // To generate a token, a user logs in to the app with an ArcGIS account that is part of an // organization in ArcGIS Online or ArcGIS Enterprise. // 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(""); if (accessToken.isEmpty()) { qWarning() << "Use of ArcGIS location services, such as the basemap styles service, requires" << "you to authenticate with an ArcGIS account or set the API Key property."; } else { ArcGISRuntimeEnvironment::setApiKey(accessToken); } -
Save main.cpp file.
Best Practice: The access token is stored directly in the code as a convenience for this tutorial. Do not store credentials directly in source code in a production environment.
Run the app
Press Ctrl + R to run the app.
You should see a map centered on the Santa Monica Mountains in California, with an address search bar at the top. Input an address in the search bar and the app will present a list of suggested addresses (not limited to the displayed map area). Click an address to zoom to that address location.
What's next?
Learn how to use additional API features, ArcGIS location services, and ArcGIS tools in these tutorials: