His historical work had strong bibliographical and cartographical elements. The U.S. Geological Survey (USGS) uses this cartographical definition. Between 1924 and 1930 Krasovsky headed astronomical, geodetical and cartographical works in the USSR. Norden frequently experienced difficulty in finding patronage for his cartographical and chorographical work. Berghaus is most famous in connection with his cartographical work. He served in Senegal, where his duties included cartographical surveys. This was considered the pinnacle of his cartographical endeavors. There is no cartographical or written evidence for this alleged discovery. His cartographical output was large and varied. He based many of his cartographical studies on the work of Timothy Pont. He graduated as a cartographical instrument-maker in 1939. There is also no cartographical proof of this supposed discovery. The Fra Mauro world map is a major cartographical work.