Table 2. Typology of the development stages of the coupling coordination degree of urbanization and ecological environment.

Primary stages		Basic stages
Superior balanced development	$0.8<D\le 1$	$g(E)-f(U)>0.1$	Superiorly balanced development with lagging urbanization
		$f(U)-g(E)>0.1$	Superiorly balanced development with a lagging ecological environment
		$0\le \left|f(U)-g(E)\right|\le 0.1$	Superiorly balanced development of urbanization and ecological environment
Barely balanced development	$0.5<D\le 0.8$	$g(E)-f(U)>0.1$	Barely balanced development with lagging urbanization
		$f(U)-g(E)>0.1$	Barely balanced development with a lagging ecological environment
		$0\le \left|f(U)-g(E)\right|\le 0.1$	Barely balanced development of urbanization and ecological environment
Slightly unbalanced development	$0.3<D\le 0.5$	$g(E)-f(U)>0.1$	Slightly unbalanced development with hindered urbanization
		$f(U)-g(E)>0.1$	Slightly unbalanced development with a hindered ecological environment
		$0\le \left|f(U)-g(E)\right|\le 0.1$	Slightly unbalanced development of urbanization and ecological environment
Seriously unbalanced development	$0<D\le 0.3$	$g(E)-f(U)>0.1$	Seriously unbalanced development with hindered urbanization
		$f(U)-g(E)>0.1$	Seriously unbalanced development with a hindered ecological environment
		$0\le \left|f(U)-g(E)\right|\le 0.1$	Seriously unbalanced development of urbanization and ecological environment