- Qt 6.9
- Qt Location
- QML Types
- MapPolyline
- Qt 6.9.0 Reference Documentation

# MapPolyline QML Type

The MapPolyline type displays a polyline on a map. More...

Import Statement: | `import QtLocation 6.9`
Since: | QtLocation 5.0

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

## Properties

- autoFadeIn : bool
- line
  - line.color : color
  - line.width : int
- path : list<coordinate>
- referenceSurface : enum `(since 6.5)`

## Methods

- void addCoordinate(coordinate)
- coordinate containsCoordinate(coordinate) `(since QtLocation 5.6)`
- coordinate coordinateAt(index) `(since QtLocation 5.6)`
- void insertCoordinate(index, coordinate) `(since QtLocation 5.6)`
- int pathLength() `(since QtLocation 5.6)`
- void removeCoordinate(coordinate)
- void removeCoordinate(index) `(since QtLocation 5.6)`
- void replaceCoordinate(index, coordinate) `(since QtLocation 5.6)`
- void setPath(geopath path)

## Detailed Description

The MapPolyline type displays a polyline on a map, specified in terms of an ordered list of coordinates. The coordinates on the path cannot be directly changed after being added to the Polyline. Instead, copy the path into a var, modify the copy and reassign the copy back to the path.

     var path = mapPolyline.path;
     path[0].latitude = 5;
     mapPolyline.path = path;

Coordinates can also be added and removed at any time using the addCoordinate and removeCoordinate methods.

By default, the polyline is displayed as a 1-pixel thick black line. This can be changed using the line.width and line.color properties.

### Example Usage

The following snippet shows a MapPolyline with 4 points, making a shape like the top part of a "question mark" (?), near Brisbane, Australia. The line drawn is 3 pixels in width and green in color.

     Map {
         MapPolyline {
             line.width: 3
             line.color: 'green'
             path: [
                 { latitude: -27, longitude: 153.0 },
                 { latitude: -27, longitude: 154.1 },
                 { latitude: -28, longitude: 153.5 },
                 { latitude: -29, longitude: 153.5 }
             ]
         }
     }

## Property Documentation

autoFadeIn : bool

This property holds whether the item automatically fades in when zooming into the map starting from very low zoom levels. By default this is `true`. Setting this property to `false` causes the map item to always have the opacity specified with the QtQuick::Item::opacity property, which is 1.0 by default.

line group
line.color : color
line.width : int

This property is part of the line property group. The line property group holds the width and color used to draw the line.

The width is in pixels and is independent of the zoom level of the map. The default values correspond to a black border with a width of 1 pixel.

For no line, use a width of 0 or a transparent color.

path : list<coordinate>

This property holds the ordered list of coordinates which define the polyline.

referenceSurface : enum `[since 6.5]`

This property determines the reference surface of the polyline. If it is set to QLocation::ReferenceSurface::Map the polylines vertices are connected with straight lines on the map. If it is set to QLocation::ReferenceSurface::Globe, the vertices are connected following the great circle path, describing the shortest connection of two points on a sphere. Default value is QLocation::ReferenceSurface::Map.

This property was introduced in Qt 6.5.

## Method Documentation

void addCoordinate(coordinate)

Adds the specified coordinate to the end of the path.

See also insertCoordinate, removeCoordinate, and path.

`[since QtLocation 5.6]` coordinate containsCoordinate(coordinate)

Returns true if the given coordinate is part of the path.

This method was introduced in QtLocation 5.6.

`[since QtLocation 5.6]` coordinate coordinateAt(index)

Gets the coordinate of the polyline at the given index. If the index is outside the path's bounds then an invalid coordinate is returned.

This method was introduced in QtLocation 5.6.

`[since QtLocation 5.6]` void insertCoordinate(index, coordinate)

Inserts a coordinate to the path at the given index.

This method was introduced in QtLocation 5.6.

See also addCoordinate, removeCoordinate, and path.

`[since QtLocation 5.6]` int pathLength()

Returns the number of coordinates of the polyline.

This method was introduced in QtLocation 5.6.

See also path.

void removeCoordinate(coordinate)

Removes coordinate from the path. If there are multiple instances of the same coordinate, the one added last is removed.

If coordinate is not in the path this method does nothing.

See also addCoordinate, insertCoordinate, and path.

`[since QtLocation 5.6]` void removeCoordinate(index)

Removes a coordinate from the path at the given index.

If index is invalid then this method does nothing.

This method was introduced in QtLocation 5.6.

See also addCoordinate, insertCoordinate, and path.

`[since QtLocation 5.6]` void replaceCoordinate(index, coordinate)

Replaces the coordinate in the current path at the given index with the new coordinate.

This method was introduced in QtLocation 5.6.

See also addCoordinate, insertCoordinate, removeCoordinate, and path.

void setPath(geopath path)

Sets the path using a geopath type.

See also path.