- Qt 6.8
- Qt Location
- QML Types
- MapItemGroup
- Qt 6.8.2 Reference Documentation

# MapItemGroup QML Type

The MapItemGroup type is a container for map items. More...

Import Statement: | `import QtLocation 6.8`
Since: | QtLocation 5.9

- List of all members, including inherited members
- MapItemGroup is part of QML Maps Plugin.

## Detailed Description

Its purpose is to enable code modularization by allowing the usage of qml files containing map elements related to each other, and the associated bindings.

Note: The release of this API with Qt 5.9 is a Technology Preview.

### Example Usage

The following snippet shows how to use a MapItemGroup to create a MapCircle, centered at the coordinate (63, -18) with a radius of 100km, filled in red, surrounded by an ondulated green border, both contained in a semitransparent blue circle with a MouseArea that moves the whole group. This group is defined in a separate file named PolygonGroup.qml:

     import QtQuick
     import QtPositioning
     import QtLocation

     MapItemGroup {
         id: itemGroup
         property alias position: mainCircle.center
         property var radius: 100 * 1000
         property var borderHeightPct : 0.3

         MapCircle {
             id: mainCircle
             center : QtPositioning.coordinate(40, 0)
             radius: itemGroup.radius * (1.0 + borderHeightPct)
             opacity: 0.05
             visible: true
             color: 'blue'

             MouseArea{
                 anchors.fill: parent
                 drag.target: parent
                 id: maItemGroup
             }
         }

         MapCircle {
             id: groupCircle
             center: itemGroup.position
             radius: itemGroup.radius
             color: 'crimson'

             onCenterChanged: {
                 groupPolyline.populateBorder();
             }
         }

         MapPolyline {
             id: groupPolyline
             line.color: 'green'
             line.width: 3

             function populateBorder() {
                 groupPolyline.path = [] // clearing the path
                 var waveLength = 8.0;
                 var waveAmplitude = groupCircle.radius * borderHeightPct;
                 for (var i=0; i <= 360; i++) {
                     var wavePhase = (i/360.0 * 2.0 * Math.PI )* waveLength
                     var waveHeight = (Math.cos(wavePhase) + 1.0) / 2.0
                     groupPolyline.addCoordinate(groupCircle.center.atDistanceAndAzimuth(groupCircle.radius + waveAmplitude * waveHeight , i))
                 }
             }

             Component.onCompleted: {
                 populateBorder()
             }
         }
     }

PolygonGroup.qml is now a reusable component that can then be used in a Map as:

     Map {
         id: map
         PolygonGroup {
             id: polygonGroup
             position: QtPositioning.coordinate(63,-18)
         }
     }