As a keen student of countries and races, Rizal realized the value of skills in geography. He knew that geography is an important shaper of history for it affects a people's way of life and the events that take place around them.
Rizal acquired his extensive knowledge of geography through his numerous travels abroad; by pouring over geography books and maps; and by mingling with the famous geographers of Europe, including Dr. W. Joest of Berlin. In recognition of his geographical expertise and his deep interest in geography, he was admitted in February 1887 as a member of the renowned Geographic Society of Berlin. He was the first Asian scholar to become a member of the society.
As a geographer, Rizal rendered valuable services to his Austrian friend, Professor Ferdinand Blumentritt. He furnished Blumentritt with vital information on Philippine geography that the latter needed in his ethnographic and linguistic studies. For instance, in November 1886, Rizal corrected Blumentritt's map of Mindanao in southern Philippines by adding Lake Lanao to it.
Rizal considered geography as one of the more useful disciplines and believed that it should be a required subject in school. In the curriculum he made for his proposed college in Hong Kong, he included geography as one of the main subjects together with mathematics, chemistry, physics, history, economics, law, religion, ethics, languages, and physical education.
While in exile in Dapitan, he taught a group of bright boys a wide range of subjects including geography. It is interesting to note that Rizal planned to write a school textbook on geography for children. This was one of the more ambitious projects he failed to realize because of his execution in 1896.
Rizal's expertise in geography aided him in his historical, anthropological, and political researches. Among his writings which required a good grasp of geography were "Ma-yi" (December 1888), "Tawalasi of Ibn Batuta" (January 1889), "The Philippines a Century Hence" (February 1890), "The Indolence of the Filipinos" (September 1890), "The People of Indian Archipelago" (no date), and "Notes on Melanesia, Malaysia, and Polynesia" (no date).