The Real Direccion de Trabajos Hidrograficos was an important Spanish
nautical institution, created in 1797 to compile, keep and publish, the sheer volume of information brought back from Spanish voyages of exploration in the last decades of the eighteenth century.

The separate issues of the catalogue that compose this volume, list the charts drawn and supervised by the Real Direccion de Trabajos Hidrograficos, and notes the estimated prices of the maps, as offered for sale in Spain, as well as in the Spanish overseas colonies: the prices in the colonies are consistently calculated as half of that in Spain.