 the cluster will contain 2 or more nodes. To allow clustering of single nodes you can use the <code>allowSingleNodeCluster : true</code> property.
<pre class="prettyprint lang-js">
    clusterNodeProperties: {
        allowSingleNodeCluster: true
    }
</pre>
                </td>
            </tr>
            <tr><td id="event_clusterEdgeProperties">clusterEdgeProperties</td>
                <td>Object</td>
                <td><i>Optional. </i> This is an object containing the options for the edges connec