XAML-Map-Control/MapControl/Avalonia/MapPath.Avalonia.cs

using Avalonia;
using Avalonia.Controls.Shapes;
using Avalonia.Media;

namespace MapControl;

public partial class MapPath : Shape
{
    public static readonly StyledProperty<Geometry> DataProperty =
        DependencyPropertyHelper.AddOwner<MapPath, Geometry>(Path.DataProperty,
            (path, oldValue, newValue) => path.UpdateData());

    public Geometry Data
    {
        get => GetValue(DataProperty);
        set => SetValue(DataProperty, value);
    }

    protected override Geometry CreateDefiningGeometry() => Data;
}