maps.qdoc

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// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
 
/*!
\page location-maps-qml.html
\title Maps and Navigation (QML)
 
\brief Provides QtQuick user interfaces for displaying, navigating and
       interacting with maps, as well as geocoding and navigation.
 
\b{Maps and Navigation} provides QtQuick user interface types for
displaying geographic information on a map, as well as allowing user
interaction with map overlay objects and the display itself. It also
contains utilities for geocoding (finding a geographic coordinate from a
street address) and navigation (including driving and walking directions).
 
To perform navigation we need \l {route}s from start to destination. These
routes are made up of segments, where each \l {QtLocation::}{routeSegment} can
be considered a navigation subtask; for example, "drive 100 meters", or "turn
left". The beginning and end of each segment is a \e waypoint, that is, one part
of the journey.
 
A typical use case for the API is a user looking for a particular type of place,
such as a restaurant; the user enters a search string into the map application
and is presented with a list of results for restaurants "near" the device. The
application can then be used to navigate to the chosen destination using a route
that is optimized according to features in the environment that may help or
hinder the journey. The navigation then proceeds with the user's progress
monitored by means of the current location.
 
The types build upon the API concepts and types in the
\l{Positioning (QML)}{QML Positioning API}. A more hands-on introduction of the
Maps and Navigation types can be found in the
\l {QML Maps}{Maps and Navigation tutorial}.
 
\section1 Maps
 
\section2 Displaying Maps
 
Displaying a map is done using the \l{QtLocation::Map}{Map} QML types.  The Map type supports
user interaction through the \l{QtLocation::MapView}{MapView} QML type. The Map
object draws the map on-screen using OpenGL (ES), allowing for hardware-accelerated rendering
where available.
 
\b{Key Types}
\table
    \row
        \li \l{QtLocation::Plugin}{Plugin}
        \li A location-based services plugin provides data including map data which is then displayed in a Map object.
    \row
        \li \l{QtLocation::Map}{Map}
        \li QtQuick item to display a map on-screen.
    \row
        \li \l{QtLocation::MapView}{MapView}
        \li Interaction helper for panning, flicking and pinch-to-zoom gesture on a Map.
\endtable
 
Note that the client must create a \l{QtLocation::Plugin}{Plugin} object
prior to using a \l{QtLocation::Map}{Map} type in order to have access
to map data to display.
 
\section2 Putting Objects on a Map (Map Overlay Objects)
 
Maps can also contain map overlay objects, which are used to display information
on its surface. There is a set of basic pre-defined map overlay objects, as well
as the ability to implement custom map overlay objects using the
\l{QtLocation::MapQuickItem}{MapQuickItem} type, which can contain any
standard QtQuick item.
 
\b{Key Types}
\table
    \row
        \li \l{QtLocation::MapCircle}{MapCircle}
        \li A geographic circle (all points at a set distance from a center), optionally with a border.
    \row
        \li \l{QtLocation::MapRectangle}{MapRectangle}
        \li A rectangle whose top left and bottom right points are specified as
            \l {coordinate} types, optionally with a border.
    \row
        \li \l{QtLocation::MapPolygon}{MapPolygon}
        \li A polygon made of an arbitrary list of \l {coordinate}{coordinates}.
    \row
        \li \l{QtLocation::MapPolyline}{MapPolyline}
        \li A polyline made of an arbitrary list of \l {coordinate}{coordinates}.
    \row
        \li \l{QtLocation::MapQuickItem}{MapQuickItem}
        \li Turns any arbitrary QtQuick Item into a map overlay object.  MapQuickItem is an enabler for specifying custom map overlay objects.
\endtable
 
\section2 Model-View Design with Map Overlay Objects
 
To automatically generate map overlay objects based on the contents of a QtQuick
model (for example a ListModel item), the \l{QtLocation::MapItemView}{MapItemView}
type is available. It accepts any map overlay object as its delegate, and can
only be created within a \l{QtLocation::Map}{Map}.
 
\b{Key Types}
\table
    \row
        \li \l{QtLocation::MapItemView}{MapItemView}
        \li Populates a Map with map overlay objects based on the data provided by a model.
\endtable
 
\section2 Interaction with Map Overlay Objects
 
Properties of map overlay objects that influence their appearance on the display can
be changed at any time, and many can also be used in animations. Animating
coordinate-based map overlay objects, such as MapPolygon and MapPolyline, is not yet
available.
 
\section1 Geocoding -- Address to Coordinate and Vice Versa
 
Geocoding is the translation of geographic coordinates into addresses, or vice
versa.  Such a translation usually involves sending the source data to a server
which then performs the translation and returns the results, although some
location-based service provider \l{QtLocation::Plugin}{plugins} may be able to
provide some geocoding functionality without sending data to a remote server.
The availability and accuracy of the translation usually depends on the location
or address being translated, as different areas of the Earth are mapped to
varying degrees of accuracy.
 
A geocoding query in QML is performed using the
\l{QtLocation::GeocodeModel}{GeocodeModel} type. For an address-to-coordinate
query, its \c{query} property may be set to either an
\l [QtPositioning]{Address} object or a string containing the textual
form of the address to search for. To perform the reverse, the same property
can be set to a \l {coordinate} instead. Results are made available in the
contents of the model.
 
\b{Key Types}
\table
    \row
        \li \l{QtLocation::Plugin}{Plugin}
        \li A location-based services plugin provides data including geocoding translation results which are exposed to clients via a GeocodeModel.
    \row
        \li \l{QtLocation::GeocodeModel}{GeocodeModel}
        \li Queries the Plugin for geocoding translations and provides access to results via indexes in the model.
    \row
        \li \l[QtPositioning]{Address}
        \li Structured address for use in queries and results of geocoding.
\endtable
 
Note that the client must create a \l{QtLocation::Plugin}{Plugin} object
prior to using a \l{QtLocation::GeocodeModel}{GeocodeModel} object. This
will enable access to geocoding translation services and thus data to display.
 
\section1 Routing and Navigation
 
Routing is the determination of a navigable path from one point to another on
a map. Given a map that is aware of features that aid or hinder navigation, such as
bridges, waterways and so on, a series of segments that make
up the journey can be constructed. If these \l {routeSegment}s are simple then we can
add navigation information at the connecting points, \l {routeManeuver}s,
between the segments.
 
\b{Key Types}
\table
    \row
        \li \l route
        \li The entire path to be navigated.
    \row
        \li \l{QtLocation::routeSegment}{routeSegment}
        \li The individual components of a route.
    \row
        \li \l{QtLocation::routeManeuver}{routeManeuver}
        \li The navigation information that joins segments.
    \row
        \li \l{QtLocation::RouteModel}{RouteModel}
        \li The means of making requests on the backend to supply route
        information.
\endtable
 
 
 
 
 
 
*/
 
 
/*!
\page location-maps-cpp.html
\title Maps and Navigation (C++)
 
\brief Provides C++ classes for Geocoding and Navigation.
 
\b{Maps and Navigation} provides C++ utilities for geocoding (finding a
geographic coordinate from a street address) and navigation (including driving
and walking directions).
 
Currently it is not possible to interact with maps via C++. Mapping applications
must use the \l {Maps and Navigation (QML)} API.
 
 
\section1 Geocoding
 
In C++, an address-to-coordinate query is performed using the
\l{QGeoCodingManager::geocode()}{geocode()} method of the QGeoCodingManager
class. For coordinate-to-address queries, the
\l{QGeoCodingManager::reverseGeocode()}{reverseGeocode()} method is available
on the same class. Instances of QGeoCodingManager are available via
\l{QGeoServiceProvider}.
 
\b{Key Classes}
\table
    \row
        \li \l{QGeoServiceProvider}
        \li Provides a QGeoCodingManager instance ready for use.
    \row
        \li \l{QGeoCodingManager}
        \li Accepts queries and produces QGeoCodeReply objects.
    \row
        \li \l{QGeoCodeReply}
        \li Contains the results of a geocoding query.
\endtable
 
\section1 Navigation
 
In C++, a route query is performed using the \l{QGeoRoutingManager::calculateRoute()}{calculate()}
method of the QGeoRoutingManager class. The returned route reply can contain
multiple routes to the same destination.
 
\b{Key Classes}
\table
    \row
        \li \l{QGeoServiceProvider}
        \li Provides a QGeoCodingManager instance ready for use.
    \row
        \li \l{QGeoRoutingManager}
        \li Accepts queries and produces QGeoRouteReply objects.
    \row
        \li \l{QGeoRouteReply}
        \li Contains the results of a routing query.
    \row
        \li \l{QGeoRoute}
        \li Contains information about a route.
\endtable
 
 
*/