="../../property_map/doc/ReadWritePropertyMap.html">ReadWritePropertyMap</a>. The
<TT>key_type</TT> of the color map must be the
<TT>vertex_descriptor</TT> from the graph, and the <TT>value_type</TT>
must be some kind of integer. We also specify the interface for the
<TT>order</TT> parameter as a property map, in this case a <a
href="../../property_map/doc/ReadablePropertyMap.html">ReadablePropertyMap</a>. For
order, the <TT>key_type</TT> is an integer offset and the
<TT>value_type</TT> is a <TT>vertex_desc