internal void RemoveLocation3DAsset(Location3DAsset resource)
    {
        var annotations = m_markerAnnotations[resource.Id];

        m_markerAnnotations.RemoveAll(resource.Id);

        if (annotations != null)
        {
            foreach (var ann in annotations)
            {
                RemoveAnnotation(ann);
            }
        }
    }
    internal void AddLocation3DAsset(Location3DAsset resource)
    {
        if (resource.Locations != null)
        {
            foreach (var l in resource.Locations)
            {
                var ann = new MapAnnotation <LocationMarker>(l);

                ann.AssetInstance = resource.AssetInstance;

                m_markerAnnotations.Add(resource.Id, ann);

                AddAnnotation(ann);
            }
        }
    }