Table 2 Classification standard of coupling-coordinated development of population economy and eco-geological environment system.

From: Evaluation on coupling coordinated development of population economy and eco-geological environment in the twin-city economic circle of Chengdu–Chongqing region

Stage

Coupling degree

Coordination level

Synergistic grade

Coordinate

0.9000–1.0000

High-quality coordinated development

Advanced synergy

0.8000–0.8999

Well coordinated development

0.7000–0.7999

Intermediate coordinated development

Primary synergy

0.6000–0.6999

Primary coordinated development

Transition

0.5000–0.5999

Reluctantly coordinated development

Basic synergy

0.4000–0.4999

On the verge of imbalance antagonism

Antagonism

0.3000–0.3999

Mild maladjustment antagonism

Basic maladjustment

0.2000–0.2999

Moderate imbalance antagonism

0.1000–0.1999

Severe imbalance antagonism

Serious maladjustment

0.0000–0.0999

Extreme imbalance antagonism