This rare map appeared in Antonio de Ulloa and Jorge Juan's Relacion Historica del Viaje a la America Meridional..., a seminal work on South American geography, culture, and history written by the two scientists after nearly a decade spent exploring the continent. Spaniards Ulloa and Juan were appointed to the French Geodesic Mission to South America. The purpose of the mission was to measure a degree of meridian arc at the equator, and the chosen location for the measurements was Ecuador. The measurements would then be compared with similar measurements made near the North Pole, with the goal of determining the true shape of the earth.

This map gives great topographical detail of the area to the east and west of Quito, Ecuador. A series of triangulation lines are depicted based on the measurements by Antonio de Ulloa and Jorge Juan. Numerous small towns, villages, rudimentary roads, and even volcanoes are identified. The decorative title cartouche features a native family with a volcano in the background and a llama herder. Engraved by Jesus a Palomo. Printed on two sheets, joined as issued.

References: Shirley (BL Atlases) G.ULL-1a #5.

Condition: B

Issued folding on heavy paper with light scattered foxing and soiling, a moderate stain at right, and some offsetting at left from an opposing page of text.