For many years the agricultural revolution in England was thought to have occurred because of three major changes: the selective breeding of livestock; the removal of common property rights to land; and new systems of cropping, involving turnips and clover.
James Rennell created the first map of India. Rennell constructed the first nearly accurate map of India and published A Bengal Atlas in 1779.
I believe the answer is: Language
The research subject for international researchers are most likely to be local citizens who are not speaking the researchers' languages. This often make it really hard for the researchers to obtain and interpret the data since both the subjects and observer cannot understand each other.
