The atlas comprises a preamble, a series of detailed portolans at large scale showing regions of the continents, and a comprehensive, double-page Mappa Mundi at small scale.
In the plate showing West Africa, it is clear that Rotz used Ferro as his prime meridian for the portolans in the atlas.
Portolans derived from the Italian "portolani" - a written list of places along a coast - and were the main charts used by mariners before the 16th century.
Maps, myths and mariners Mapmaker Georgio Sideri Date 1560 This detail of Scotland and its outlying islands is taken from a portolan chart of the Mediterranean.
The text is subsidiary to the color photographs of these maps and portolans
, which represent both full images and close-ups of illuminated details.
When the weather cooperated, sailing went relatively smoothly, the ship proceeding along the coast from one recognisable landmark to another, following written 'portolans
'--texts that described the markers en mute.
From pre-Columbian Amerindian cosmography through the richness of medieval mappae mundi, from Japanese portolans
to the barrage of 19th-century British Admiralty charts, maps made and manipulated an expanding realm of understanding.
The maps of the fifteenth and sixteenth centuriues were primarily portolans
and roteiros detailing coastal settlements, but not of the interior.
Only when sea navigation became important did the need for better charting methods become urgent as until then ships had to rely on the portolans, which were made up of innumerable small, flat projections.
The oldest portolan is in the National Library in Paris and called the Carta Pisana, being a collection of small maps taken from pilot books, or rutters.
While the maps were almost abstract at the beginning, over centuries, many users enriched portolans
with iconography that even today makes us dream.
charts were the fruits of the first systematic marine surveys.