The cartographers Petermann trained included Bruno Hassenstein (1839–1902), Hermann Habenicht (1844–1917, who from 1897 onwards trained Hermann Haack, the 20th-century editor of PGM), Ernst Debes (1840–1923. He could have come to rival Carl Vogel, but in 1868 he left the Gotha Institute to co-found his own firm, Wagner & Debes, which published one of the six famous families of German reference atlases "E. Debes neuer Handatlas", later called "Grosser Columbus Weltatlas"), Carl Barich, Arnim Welcker (1840–1859), Ludwig Friederichsen (who worked on the Stieler and PGM from 1859 to 1863, and later founded the geographical society of Hamburg and became very active in German colonial politics.) in the 1850s, and Fritz Hanemann (1847–1877), Christian Peip (1843–1922), Bruno Domann and Otto Koffmahn (1851–1916) in the 1860s. They soon learned to produce maps as good as their teacher's, and eventually even better. But they had probably listened well when Petermann pointed out the need for an improvement in map lettering, in elevation figures (though elevation and bathymetric figures were common in topographic maps and charts, Petermann was the first to include them in geographic maps), more accurate engraving and better coloring, for under his directions the maps of the Stieler became more uniform in expression. In this they were also guided by the more than consistent work of Vogel, and Von Sydow's critical remarks concerning the advantages and disadvantages of certain styles in his "Kartographischen Standpunkt Europas".