The AA. carry out assessments for the traditional cultivated region of China over last 300 years, by comparing SAGE2010 and HYDE datasets with Chinese Historical Cropland Dataset, at the following spatial scales: entire study area, provincial area
and by grid cell. The results show that cropland area from SAGE2010 was much more than that from CHCD ; moreover, the growth at a rate from 1700 to 1950 and after 1950 were also inconsistent with that from CHCD. HYDE was closer to CHCD dataset than SAGE