Notable geographers

Henestaríneos (276BC - 194BC) - calculated the size of the Earth.
Strabo (64/63 BC – ca. AD 24) - wrote Geographica, one of the first books outlining the study of geography.
Ptolemy (c.90–c.168) - compiled Greek and Roman knowledge into the book Geographia.
Al Idrisi (Arabic: أبو عبد الله محمد الإدريسي; Latin: Dreses) (1100–1165/66) - author of Nuzhatul Mushtaq.
Gerardus Mercator (1512–1594) - innovative cartographer produced the mercator projection
Gerardus Mercator
Alexander von Humboldt (1769–1859) - Considered Father of modern geography, published the Kosmos and founder of the sub-field biogeography.
Carl Ritter (1779–1859) - Considered Father of modern geography. Occupied the first chair of geography at Berlin University.
Arnold Henry Guyot (1807–1884) - noted the structure of glaciers and advanced understanding in glacier motion, especially in fast ice flow.
William Morris Davis (1850–1934) - father of American geography and developer of the cycle of erosion.
Paul Vidal de la Blache (1845–1918) - founder of the French school of geopolitics and wrote the principles of human geography.
Sir Halford John Mackinder (1861–1947) - Co-founder of the LSE, Geographical Association
Carl O. Sauer (1889–1975) - Prominent cultural geographer
Walter Christaller (1893–1969) - human geographer and inventor of Central place theory.
Yi-Fu Tuan (1930-) - Chinese-American scholar credited with starting Humanistic Geography as a discipline.
Karl W. Butzer (1934-) - An influential German-American geographer, cultural ecologist and environmental archaeologist.
David Harvey (1935-) - Marxist geographer and author of theories on spatial and urban geography, winner of the Vautrin Lud Prize.
Edward Soja (born 1941) - Noted for his work on regional development, planning and governance along with coining the terms Synekism and Postmetropolis.
Michael Frank Goodchild (1944-) - prominent GIS scholar and winner of the RGS founder's medal in 2003.
Doreen Massey (1944-) - Key scholar in the space and places of globalization and its pluralities, winner of the Vautrin Lud Prize.
Nigel Thrift (1949-) - originator of non-representational theory.
Ellen Churchill Semple (1863–1932) - She was America's first influential female geographer.

Source: Wikipedia