How to: Aggregate Vector Items Using a Clusterer

• Apr 15, 2018
• 2 minutes to read

To aggregate vector items using the clusterer, assign a MapClustererBase class descendant to the MapDataAdapterBase.Clusterer property. Then optionally, specify the clusterer’s properties.

For example, all predefined clusterers allow you to group items before clustering and customize the appearance of cluster representatives.

To group items, assign AttributeGroupProvider to the MapClusterer.GroupProvider property. Then, set the provider’s AttributeGroupProvider.AttributeName property to location.

To customize the appearance of cluster representatives, assign the required MapItemSettings class descendant object to the MapClusterer.ClusterSettings property.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-aggregate-vector-items-using-a-clusterer-t311923.

MainWindow.xaml.cs

using System.Windows;
using DevExpress.Xpf.Map;

namespace ClustererSample {
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
        }

        private void MarkerClusterer_Clustered(object sender, ClusteredEventArgs e) {
            map.ZoomToFitLayerItems();
        }
    }
}

MainWindow.xaml

<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:ClustererSample"
        xmlns:dxm="http://schemas.devexpress.com/winfx/2008/xaml/map" 
        x:Class="ClustererSample.MainWindow"
        mc:Ignorable="d"
        Title="MainWindow" Height="720" Width="1280">
    <Window.Resources>
        <XmlDataProvider x:Key="dataSource" Source="Data/TreesCl.xml" />
    </Window.Resources>

    <Grid>

        <dxm:MapControl x:Name="map">
            <dxm:ImageTilesLayer>
                <dxm:BingMapDataProvider BingKey="YourBingKeyHere"/>
            </dxm:ImageTilesLayer>
            <dxm:VectorLayer>
                <dxm:ListSourceDataAdapter DataSource="{Binding Source={StaticResource dataSource}}"
                                           DataMember="Row">
                    <dxm:ListSourceDataAdapter.Mappings>
                        <dxm:MapItemMappingInfo Latitude="lat" 
                                                Longitude="lon"/>
                    </dxm:ListSourceDataAdapter.Mappings>
                    <dxm:ListSourceDataAdapter.AttributeMappings>
                        <dxm:MapItemAttributeMapping Name="location" 
                                                     Member="location"/>
                    </dxm:ListSourceDataAdapter.AttributeMappings>
                    <dxm:ListSourceDataAdapter.ItemSettings>
                        <dxm:MapDotSettings/>
                    </dxm:ListSourceDataAdapter.ItemSettings>
                    <dxm:ListSourceDataAdapter.Clusterer>
                        <dxm:MarkerClusterer Clustered="MarkerClusterer_Clustered">
                            <dxm:MarkerClusterer.GroupProvider>
                                <dxm:AttributeGroupProvider AttributeName="location"/>
                            </dxm:MarkerClusterer.GroupProvider>
                            <dxm:MarkerClusterer.ClusterSettings>
                                <dxm:MapDotSettings/>
                            </dxm:MarkerClusterer.ClusterSettings>
                        </dxm:MarkerClusterer>
                    </dxm:ListSourceDataAdapter.Clusterer>
                </dxm:ListSourceDataAdapter>
            </dxm:VectorLayer>
        </dxm:MapControl>

    </Grid>
</Window>

MainWindow.xaml.vb

Imports System.Windows
Imports DevExpress.Xpf.Map

Namespace ClustererSample
    Partial Public Class MainWindow
        Inherits Window

        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub MarkerClusterer_Clustered(ByVal sender As Object, ByVal e As ClusteredEventArgs)
            map.ZoomToFitLayerItems()
        End Sub
    End Class
End Namespace

Application.xaml.vb

Imports System
Imports System.Collections.Generic
Imports System.Configuration
Imports System.Data
Imports System.Linq
Imports System.Threading.Tasks
Imports System.Windows

Namespace ClustererSample
    ''' <summary>
    ''' Interaction logic for App.xaml
    ''' </summary>
    Partial Public Class App
        Inherits Application

    End Class
End Namespace

Application.xaml

<Application x:Class="ClustererSample.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:ClustererSample"
             StartupUri="MainWindow.xaml">
    <Application.Resources>

    </Application.Resources>
</Application>