Adaptive boosting Bayesian networks Beijing [China] China Concentration change Concentration retrieval Decision tree regression Decision trees Dimensionality reduction Landsat Learning systems Machine learning algorithm Miyun Reservoir Miyun reservoir , China Neural networks Nitrogen Remote sensing Reservoir management Reservoirs (water) Retrieval model River pollution Rural areas Scientific references Spatial distribution Spatial heterogeneity Support vector machines Support vector regression Total nitrogen concentration UAV hyper spectral remote sensing data Unmanned aerial vehicles (UAV)