Study on Comprehensive Grade Evaluation of River Health to Yihe River Based on Projection Pursuit of Entropy

Comprehensive grade evaluation by nine evaluation indexes of river health based on projection pursuit of entropy is proposed as a new evaluation approach in this paper. The results of this model applied to evaluate Yihe river show that the calculated membership degree value of river health fuzzy set is 0. 551,so Yihe River belongs to the grade of interior health,which is coincide with the results of AHP. The results show the model is effective and general and can be widely applied to various comprehensive evaluation of environmental quality.