Apparently Eratosthenes could be described as the first geographer. He was born in 276 BC in Cyrene (now Libya) and died at the pretty good age of 82 in Alexandria. He was a mathematician and philosopher (weren't they all in those days) and was the first person to measure the circumference of the earth.
He was accused of being a jack of all trades but master of none. Apparently his mates called him 'Beta' because he never came first at anything! Certainly he had a wide range of interests, including Geography. He sketched, quite accurately, the route of the Nile to Khartoum, showing the two Ethiopian tributaries. He also suggested that lakes were the source of the river. A study of the Nile had been made by many scholars before Eratosthenes and they had attempted to explain the rather strange behaviour of the river, but most like Thales were quite wrong in their explanations. Eratosthenes was the first to give what is essentially the correct answer when he suggested that heavy rains sometimes fell in regions near the source of the river and that these would explain the flooding lower down the river. Another contribution that Eratosthenes made to geography was his description of the region "Eudaimon Arabia", now the Yemen, as inhabited by four different races. The situation was somewhat more complicated than that proposed by Eratosthenes, but today the names for the races proposed by Eratosthenes, namely Minaeans, Sabaeans, Qatabanians, and Hadramites, are still used.
Somehow he also found time to write. His writings include the poem Hermes, inspired by astronomy, as well as literary works on the theatre and on ethics which was a favourite topic of the Greeks. Eratosthenes is said to have became blind in old age and it has been claimed that he committed suicide by starvation. Not something for modern day Geographers to emulate, though I guess blindness in those days must have really stopped all his interests.
What I wonder would he have made of Google Earth?