asets of the <code>"sdam"</code> package. For instance, four cartographical maps related to the Roman Empire in the antiquity period are available in dataset <code>"retn"</code> that is loaded by function <code><a href="../reference/plot.map.html">plot.map()</a></code> to depict cartographical maps and transportation systems. <code><a href="../reference/plot.map.html">plot.map()</a></code> is an interface that also invokes datasets <code>"rpmp"</code> for names and vector shapes of Roman provinces and regio