Study on Ecological Risk Evaluation and Optimum Selection of Desert Expressway Schemes Based on the Two-Dimensional Cloud Model

Table 2

Description of economic cost levels.

Evaluation criterion	Class	Specific description	Subinterval score	Standard digital features
Excellent	I	Very economical, the cost is negligible	[7.5, 10]	(8.75, 0.42, 0.01)
Good	II	More economical, moderate cost	[5.0, 7.5]	(6.25, 0.42, 0.01)
General	III	Not economical, the cost is close to rebuilding	[2.5, 5.0]	(3.75, 0.42, 0.01)
Poor	IV	Repair costs more than rebuilding	[0.0, 2.5]	(1.25, 0.42, 0.01)