The study looked at how the land in Changsha changed from 2003 to 2013. Using satellite images and special technology, the researchers found that the amount of farmland decreased, while building areas increased. Forest areas first grew, then shrank. Most farmland and forest turned into buildings, especially at the edge of the city. As the city grew, more farmland was lost and more buildings were made. The researchers also found that as the city urbanized, industries and people also grew. The relationship between land changes and urbanization went through three stages: city spreading out, city growing faster, and city expanding rapidly.