The plan makes an ecological suitability analysis and construction suitability appraisal to the soil within the scope, and divides the site into four categories: forbidden area, limited area, built area and buildable area. Base on the spatial division and through the analysis to ecology and transportation in the region as well as the study to green transportation, neighborhood units and ecological communities, a special structure is pinned down, "one core, one chain and six wedges; one axis, three centers and four areas".
In the sub-structural planning, it defines the "six lines" control scope in red, green, blue, purple, yellow and black in a quantitative and qualitative way and brings forward the corresponding requirements for spatial control.
Red line: the boundary line of both sides of legally planned and constructed urban roads in the urban planning area
Green line: the boundary line of legally planned and constructed urban green land in the urban planning area
Purple line: the boundary line of legally planned and constructed historic-cultural districts and marking the protection of historic architectures in the urban planning area
Blue line: the regional line marking the protection and control of urban surface water body specified in the urban plan including rivers, lakes, reservoirs, dykes and wetlands etc.
Yellow line: the boundary line of land for urban infrastructure influencing the overall urban development and specified in urban planning, which must be controlled.
Black line: the boundary line of transit facilities such as railway, light railway, metro (ground segment).
