Gastaldi's map of Mexico and the Southwest is the first printed map to focus on the Southern half of the United States and Mexico, including Florida and Texas.
Gastaldi's highly influential map is a composite of the latest discoveries in the region. The placenames reflect the explorations of Pineda, Cabeza de Vaca, and Moscosso. R. Spiritu Santu appears (Mississippi River). California is showns as a Peninsula, one of the earliest depictions of California on a printed map (first shown by Cabot in 1544). The R. Tontonteanc is either the Gila or the Colorado River. Florida and Cuba are named. The Yucatan appears as an island, which would later be corrected in Ruscelli's map of 1561.
Perhaps the most influential map of the southwest during the 16th Century to appear in a commercial atlas. Not until Wyfliet's maps of 1597 would a better regional representation appear in a printed map.
Giacomo Gastaldi was the most imporant Italian mapmaker in the middle of the 16th Century, at a time when Italy was the most important of all European map printing centers. His maps published in the 1540s and 1550s were the most influential and widely copied maps in Europe until the publication of Ortelius' Theatrum Orbis Terrarum.
Giacomo Gastaldi (1500-1566) is considered the foremost Italian cartographer of the sixteenth century, alongside Paolo Forlani. His skills of compilation are comparable to those of Mercator and Ortelius, yet much less is known of his life than of his two contemporaries. Gastaldi was born in Villafranca, Piedmont, but had established himself in Venice by 1539. He originally worked as an engineer, but turned to mapmaking from the 1540s onward.
It was in Venice where he made his reputation as an engraver, geographer, and cosmographer; for example, he was asked to fresco maps of Asia and Africa in the Palace of the Doge, or the Council of Ten, Venice’s governmental body. He also frequently consulted on projects for the Savi sopra la Laguna, drawing maps for this body which oversaw the regulation of fresh and salt water around Venice.
His contemporaries also recognized his skill, as he was named cosmographer to the Republic of Venice, was a member of the Accademia Veneziana, and was a major source for other geographers and mapmakers including Camocio, Bertelli, Cock, Luchini, and Ortelius. He even had his own distinct style of copper engraving that made him a pioneer in his day and makes his works iconic today.
Gastaldi enjoyed an especially productive relationship with Giovanni Battista Ramusio, Secretary of the Venetian Senate, who used Gastaldi's maps for his famous travel account collection, Navigationi et Viaggi. Gastaldi also tutored Ramusio's son in cosmography.