World Heat Map

The [ObservableObject], [ObservableProperty] and [ICommand] attributes come from the CommunityToolkit.Mvvm package, you can read more about it here.

This web site wraps every sample using a ContentPage instance, but LiveCharts controls can be used inside any container.

sample image

View model

using System;
using System.Linq;
using System.Threading.Tasks;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using LiveChartsCore.Geo;
using LiveChartsCore.SkiaSharpView;
using LiveChartsCore.SkiaSharpView.Drawing.Geometries;

namespace ViewModelsSamples.Maps.World;

[ObservableObject]
public  partial class ViewModel
{
    private bool _isBrazilInChart = true;
    private readonly IWeigthedMapLand _brazil;
    private readonly Random _r = new();

    public ViewModel()
    {
        // every country has a unique identifier
        // check the "shortName" property in the following
        // json file to assign a value to a country in the heat map
        // https://github.com/beto-rodriguez/LiveCharts2/blob/master/docs/_assets/word-map-index.json
        var lands = new HeatLand[]
        {
            new() { Name = "bra", Value = 13 },
            new() { Name = "mex", Value = 10 },
            new() { Name = "usa", Value = 15 },
            new() { Name = "can", Value = 8 },
            new() { Name = "ind", Value = 12 },
            new() { Name = "deu", Value = 13 },
            new() { Name= "jpn", Value = 15 },
            new() { Name = "chn", Value = 14 },
            new() { Name = "rus", Value = 11 },
            new() { Name = "fra", Value = 8 },
            new() { Name = "esp", Value = 7 },
            new() { Name = "kor", Value = 10 },
            new() { Name = "zaf", Value = 12 },
            new() { Name = "are", Value = 13 }
        };

        Series = new HeatLandSeries[] { new HeatLandSeries { Lands = lands } };

        _brazil = lands.First(x => x.Name == "bra");
        DoRandomChanges();
    }

    public HeatLandSeries[] Series { get; set; }

    [ICommand]
    public void ToggleBrazil()
    {
        var lands = Series[0].Lands;
        if (lands is null) return;

        if (_isBrazilInChart)
        {
            Series[0].Lands = lands.Where(x => x != _brazil).ToArray();
            _isBrazilInChart = false;
            return;
        }

        Series[0].Lands = lands.Concat(new[] { _brazil }).ToArray();
        _isBrazilInChart = true;
    }

    private async void DoRandomChanges()
    {
        await Task.Delay(1000);

        while (true)
        {
            foreach (var shape in Series[0].Lands ?? Enumerable.Empty<IWeigthedMapLand>())
            {
                shape.Value = _r.Next(0, 20);
            }

            await Task.Delay(500);
        }
    }
}

XAML

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="XamarinSample.Maps.World.View"
             xmlns:lvc="clr-namespace:LiveChartsCore.SkiaSharpView.Xamarin.Forms;assembly=LiveChartsCore.SkiaSharpView.XamarinForms"
             xmlns:vms="clr-namespace:ViewModelsSamples.Maps.World;assembly=ViewModelsSamples">
    <ContentPage.BindingContext>
        <vms:ViewModel/>
    </ContentPage.BindingContext>
    <lvc:GeoMap Series="{Binding Series}" MapProjection="Mercator"/>
</ContentPage>

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