HeatmapDataSourceAdapter.Mappings Property

Contains information on how data for heatmap points should be obtained from a data source.

Namespace: DevExpress.XtraMap

Assembly: DevExpress.XtraMap.v24.1.dll

NuGet Package: DevExpress.Win.Map

Declaration

C#

public HeatmapPointMappingInfo Mappings { get; }

VB.NET

Public ReadOnly Property Mappings As HeatmapPointMappingInfo

Property Value

Type	Description
HeatmapPointMappingInfo	Provides information on the mapping of the heatmap point properties to the data fields.

Example

This example shows how to create a heatmap layer for the Map Control.

• Create an ImageLayer object and add it to the MapControl.Layers collection.
• Assign a HeatmapProvider object to the ImageLayer.DataProvider property.

C#

using DevExpress.XtraMap;
using System;
using System.Data;
using System.Drawing;
using System.Windows.Forms;

namespace HeatMapSample {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e) {

            ImageLayer bingLayer = new ImageLayer();
            bingLayer.DataProvider = new BingMapDataProvider { BingKey = "Your Bing Maps key here." };
            mapControl1.Layers.Add(bingLayer);

            ChoroplethColorizer colorizer = new ChoroplethColorizer();
            colorizer.RangeStops.AddRange(new double[] { 0.1, 0.2, 0.7, 1 });
            colorizer.ColorItems.Add(new ColorizerColorItem(Color.FromArgb(50, 128, 255, 0)));
            colorizer.ColorItems.Add(new ColorizerColorItem(Color.FromArgb(255, 255, 255, 0)));
            colorizer.ColorItems.Add(new ColorizerColorItem(Color.FromArgb(255, 234, 72, 58)));
            colorizer.ColorItems.Add(new ColorizerColorItem(Color.FromArgb(255, 162, 36, 25)));
            colorizer.ApproximateColors = true;

            HeatmapDataSourceAdapter adapter = new HeatmapDataSourceAdapter();
            adapter.Mappings.XCoordinate = "glon"; // The data source field name that provides x-coordinates.
            adapter.Mappings.YCoordinate = "glat"; // The data source field name that provides y-coordinates.
            adapter.DataSource = LoadData("../../Data/Earthquakes.xml", "Row");

            HeatmapProvider provider = new HeatmapProvider();
            provider.PointSource = adapter;
            provider.Algorithm = new HeatmapDensityBasedAlgorithm { PointRadius = 8 };
            provider.Colorizer = colorizer;

            ImageLayer heatmapLayer = new ImageLayer();
            heatmapLayer.DataProvider = provider;
            mapControl1.Layers.Add(heatmapLayer);

            ColorScaleLegend legend = new ColorScaleLegend();
            legend.Header = "Seismic Density";
            legend.EnableGradientScale = true;
            legend.Layer = heatmapLayer;
            legend.HeaderStyle.Font = new Font("Tahoma", 12F);
            mapControl1.Legends.Add(legend);
        }
        DataTable LoadData(string filePath, string tableName) {
            DataSet xmlDataSet = new DataSet("XML DataSet");
            xmlDataSet.ReadXml(filePath);
            return xmlDataSet.Tables[tableName];
        }
    }
}

VB.NET

Imports DevExpress.XtraMap
Imports System
Imports System.Data
Imports System.Drawing
Imports System.Windows.Forms

Namespace HeatMapSample

    Public Class Form1
        Inherits Form

        Public Sub New()
            MyBase.New
            InitializeComponent
        End Sub

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
            Dim bingLayer As ImageLayer = New ImageLayer
            bingLayer.DataProvider = New BingMapDataProvider() {BingKey=Your Bing Maps key here.}
            mapControl1.Layers.Add(bingLayer)

            Dim colorizer As ChoroplethColorizer = New ChoroplethColorizer
            colorizer.RangeStops.AddRange(New Double() {0.1, 0.2, 0.7, 1})
            colorizer.ColorItems.Add(New ColorizerColorItem(Color.FromArgb(50, 128, 255, 0)))
            colorizer.ColorItems.Add(New ColorizerColorItem(Color.FromArgb(255, 255, 255, 0)))
            colorizer.ColorItems.Add(New ColorizerColorItem(Color.FromArgb(255, 234, 72, 58)))
            colorizer.ColorItems.Add(New ColorizerColorItem(Color.FromArgb(255, 162, 36, 25)))
            colorizer.ApproximateColors = true

            Dim adapter As HeatmapDataSourceAdapter = New HeatmapDataSourceAdapter
            adapter.Mappings.XCoordinate = "glon" ' The data source field name that provides x-coordinates.
            adapter.Mappings.YCoordinate = "glat" ' The data source field name that provides y-coordinates.
            adapter.DataSource = Me.LoadData("../../Data/Earthquakes.xml", "Row")

            Dim provider As HeatmapProvider = New HeatmapProvider
            provider.PointSource = adapter
            provider.Algorithm = New HeatmapDensityBasedAlgorithm() {PointRadius=8}
            provider.Colorizer = colorizer

            Dim heatmapLayer As ImageLayer = New ImageLayer
            heatmapLayer.DataProvider = provider
            mapControl1.Layers.Add(heatmapLayer)

            Dim legend As ColorScaleLegend = New ColorScaleLegend
            legend.Header = "Seismic Density"
            legend.EnableGradientScale = true
            legend.Layer = heatmapLayer
            legend.HeaderStyle.Font = New Font("Tahoma", 12!)
            mapControl1.Legends.Add(legend)
        End Sub

        Private Function LoadData(ByVal filePath As String, ByVal tableName As String) As DataTable
            Dim xmlDataSet As DataSet = New DataSet("XML DataSet")
            xmlDataSet.ReadXml(filePath)
            Return xmlDataSet.Tables(tableName)
        End Function
    End Class
End Namespace