def _format_node(e):
    """
    Internal function to format a node element into a dictionary.
    """
    ignored_tags = ['source', 'source_ref', 'source:ref', 'history',
        'attribution', 'created_by', 'tiger:tlid', 'tiger:upload_uuid']
    node = {'id': e['id'], 'lat': e['lat'], 'lon': e['lon']}
    if 'tags' in e:
        for t, v in list(e['tags'].items()):
            if t not in ignored_tags:
                node[t] = v
    return node
