Petermann was also keen to use physical characteristics as background for thematic maps, an idea followed by his pupils. When Herbert Louis demanded in 1960 that the terrain underlying thematic maps should indicate elevations, hydrological networks, settlements and traffic roads, he cited Petermann as the first cartographer who used a terrain map as basis for population maps. By using hachuring as a basis for his "Karte des Österreichischen Kaiserstaates zur Übersicht der Dichtigkeit der Bevölkerung nach dem Census von 1857" (Map of the Austrian imperial state as an overview of the population density after the 1857 census, 1860) and the map "Die Ausdehnung der Slaven in der Türkei und den angrenzenden Gebieten" (Expansion of the Slavic populations in Turkey and adjacent territories, 1869) Petermann continued the representation of geological, climatological and ethnographical data that his teacher Heinrich Berghaus had begun two decades before.