Table 2. Four areas and 16 districts under this research.

4 areas	Main function	16 districts
Urban core area (city centre)	downtown and location of central government	2 districts: Dongcheng and Xicheng
Urban extended area	Main developed area	4 districts: Haidian, Chaoyang, Fengtai and Shijingshan
Urban new development area	Areas for new development	5 districts: Fangshan, Shunyi, Tongzhou, Changping and Daxing
Ecological conserving area	Limited development and providing ecological services to the city	5 districts: Mentougou, Huairou, Pinggu, Miyun and Yanqing