The Carta Marina
The full title of the map is Carta marina et Descriptio septemtrionalium terrarum ac mirabilium rerum in eis contentarum, diligentissime elaborata Annon Domini 1539 Veneciis liberalitate Reverendissimi Domini Ieronimi Quirini, which translates as "A Marine map and Description of the Northern Lands and of their Marvels, most carefully drawn up at Venice in the year 1539 through the generous assistance of the Most Honourable Lord and Patriarch Hieronymo Quirino" (Lynam 1949, 3).
Olaus’ travels and experiences in Scandinavia were his primary sources for the map. He used the maps in editions of Ptolemy’s Geographia. He obtained information, and probably charts, from mariners.
The Olaus Magnus map was a great improvement on earlier maps of Scandinavia. The general geography of Scandinavia is much more accurate. It was the largest and most detailed map of Scandinavia to its time. The blending of Ptolemy’s map projection with the mariners’ charts caused some problems; for example, Scandinavia extends two degrees beyond the North Pole.
In spite of its faults, the Carta Marina provides images of the life of the people that are both delightful to look at and rewarding to study. As Robert Karrow put it well, "For Magnus, the map was not just geography but history and ethnography as well" (Karrow 1993, 363).
That Olaus intended his map for use by navigators is clear from its title, and from the other navigational elements on the map: four large compasses, rhumb lines indicating directions from them, a pair of dividers, and distance scales. In general the ships depicted on the map are very well done, with the northern ships portrayed in their clinker-built style, indicating awareness of matters relating to ships and the sea.