What is "islario"

An islario is a Spanish term for a map showing the islands of an ocean, continent or nation.

Alonzo de Santa Cruz created a famous islario called the "Islario General" in 1542 at the request of Spanish King Phillip II. The full name of this work is Islario general de todas las islas del mundo (or roughly, general islario of all the islands in the world). This was a monumental undertaking, composed of 8 regional maps and 103 local maps, and a map of Mexico.