title: The length of coastlines in Ptolemy's<i>Geography</i>and in&amp;#160;ancient&amp;#160;<i>periploi</i>
abstract: Abstract. The lengths of the coastlines in Ptolemy's Geography are compared with the corresponding values transmitted by other ancient sources, presumably based on some lost periploi (literally "voyages around or circumnavigations", a genre of ancient geographical literature describing coastal itineraries). The comparison reveals a remarkable agreement between them, suggesting that Ptolemy relied much more heavily on these or similar periploi than it used to be thought. Additionally, a possible 
journal: History of geo- and space sciences