He proposed to follow a course East of Greenland, for he and other geographers were convinced that Greenland stretched much farther North than was known in that time. Though Ferdinand von Wrangel started a four-year-long expedition in 1820 to find possible land North of cape Shelagskiy and could not find any land he noted a Chucki chief saying: "One might in a clear summer’s day descry snow-covered mountains at a great distance to the North." Heinrich Berghaus, Petermann's teacher, included this information in the right hand corner on his isotherm map of 1838 for his "Physikalische Atlas" with the text 'possible polar land' Polar-Land. So it might be possible that Petermann based his views on this information.