Hi logimatic,

Since our markers currently don't have built in labels your approach is on the right track.  You just need to add a little bit more in order to get the marker shape itself to respect the MarkerType property.  For this you can create a DataTemplateSelector that returns one of the marker templates off the XamGeographicMap itself.  For example:

public class MyMarkerSelector : DataTemplateSelector
{
    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        Infragistics.Controls.Charts.DataContext dc = (Infragistics.Controls.Charts.DataContext)item;
        var series = dc.Series as Series;
        var markerType = MarkerSeries.ResolveMarkerType(series, (series as MarkerSeries).MarkerType);
        switch (markerType)
        {
            case MarkerType.Circle:
                return series.SeriesViewer.CircleMarkerTemplate;
            case MarkerType.Diamond:
                return series.SeriesViewer.DiamondMarkerTemplate;
            case MarkerType.Hexagon:
                return series.SeriesViewer.HexagonMarkerTemplate;
            case MarkerType.Hexagram:
                return series.SeriesViewer.HexagramMarkerTemplate;
            case MarkerType.None:
                return base.SelectTemplate(item, container);
            case MarkerType.Pentagon:
                return series.SeriesViewer.PentagonMarkerTemplate;
            case MarkerType.Pentagram:
                return series.SeriesViewer.PentagramMarkerTemplate;
            case MarkerType.Pyramid:
                return series.SeriesViewer.PyramidMarkerTemplate;
            case MarkerType.Square:
                return series.SeriesViewer.SquareMarkerTemplate;
            case MarkerType.Tetragram:
                return series.SeriesViewer.TetragramMarkerTemplate;
            case MarkerType.Triangle:
                return series.SeriesViewer.TriangleMarkerTemplate;
        }

        return base.SelectTemplate(item, container);
    }
}

Then inside your current DataTemplate, replace your Ellipse with this:

<ContentControl Content="{Binding}" ContentTemplateSelector="{StaticResource MyMarkerSelector}"
    VerticalAlignment="Center"/>

Where MyMarkerSelector is:

<local:MyMarkerSelector x:Key="MyMarkerSelector"/>