Table 2.

The four scenarios for predictions.

Scenario	Name	Description
Scenario 1 (sce 1)	Current trend	This scenario had no additional restrictions and followed the current trend for future urban growth. The excluded layer included all water bodies and 16 national nature reserves with value of 100, which meant that all the water bodies and reserve areas were fully excluded from new urban growth. The road layer also had pixel values of 100.
Scenario 2 (sce 2)	Managed trend	A policy was included for future urban growth, such as the new roads, new city, and new wetland park. The new railways and motorways included in this study were all projects planned and under construction in JJJ and the Beijing vice-center development (Figure 3). The new roads were the Jing-Xiong railway, Jing-Gang-Tai railway, Jin-Xiong railway, Jing-Kun railway, Shi-Xiong railway, Jing-Xiong motorway, Rong-Wu motorway, Jing-De motorway, and Jin-Shi motorway for the synergistic development of JJJ. In addition, the Jing-Tang railway and Jing-Qin motorway in Beijing vice-center development were added to the road layer. The new urban areas added in the urban extent layer were Xiong_An new city and Beijing Daxing International Airport. The planned Wenyu River wetland park was added to the excluded layer.
Scenario 3 (sce 3)	Ecologically sustainable I	In addition to the future policy, the farmland was partly protected in this scenario. In this case, urban development was limited and ecological resources were better protected. The farmland pixel values were set at 50, which meant farmland was 50% protected.
Scenario 4 (sce 4)	Ecologically sustainable II	In addition to policies in Scenario 3, the forest and grassland were also partly protected in this scenario, with values of 80 and 20, respectively.