Investigation Of Natural Ecological Enviroment Using Remote Sensing Based Integrated Index At A City Scale

It is of great importance to monitor and evaluate the dynamics of ecological environment due to severe human activities. In our study, three remote sensing based ecological factors were selected to generate an integrated index for estimating the natural ecological environment at a city scale, specifically including vegetation coverage, soil index and slope. Vegetation coverage was derived from Normalized Difference Vegetation Index (NDVI) of Landsat 8 OLI (Operational Land Imager) imagery. Soil index was generated by the greenness above bare soil (GRABS). Slope was derived from 30 meters resolution Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM). An integrated index with the method of weighting average was obtained by normalizing the three indicators. The results show that Hefei has a relatively good ecological environment. The ratio of excellent and good levels accounts for 71.00% of the study area. In general, the ecological environment is better in the southern part than that in the northern part.