3.2.1. Definition and Calculation of PLES Index

Land is a multi-functional complex, which can perform multiple land use functions. However, due to different land use methods, intensification, and related users, land can show the priority and level of production, living, and ecological functions [29,38]. The construction of the land use classification system of PLES is the premise of analyzing the PLES pattern. Based on the research of Liu et al. and Cui et al. [29,39], this study quantified the various functions provided by different land use types, as shown in Table 1. Besides, production space index (PSI), living space index (LSI), and ecological space index (ESI) were constructed to measure the PLES index level. The calculation equations are as follows:

where LA_i,t represents the area of land use type i at time t; n represents the number of land use types in this study; PS_i,t, LS_i,t, and ES_i,t represent the production land, living land, and ecological land score of land use type i at time t in Table 1, respectively.

Land use classification and assessment of PLES.