First flow map by Charles Joseph Minard, depicting the number of passengers traveling on roads in the area between Dijon and Mulhouse.
Charles Joseph Minard
1845
“Tableaux graphiques et cartes figuratives,” <a rel="nofollow" class="external text" href="https://patrimoine.enpc.fr/document/ENPC01_Fol_10975?image=7">Bibliothèque numérique patrimoniale des ponts et chaussées</a>