Identification of the Characteristic Scale for NDVI in the Subtropical Region of China by Use of Wavelet Analysis

Scale is the specific measurement of eco-environment in space and time. Characteristic scale is supposed to be the domain spatial size responding to the transition of system levels, the distinct heterogeneity. Normalized Difference Vegetation Index (NDVI) is usually seen as an important indicator of eco-environment. By use of wavelet analysis, the study proposes three measurement parameters to identify the NDVI characteristic scale: wavelet variance, wavelet entropy, Moran I & Geary C coefficient. Results show that the corresponding scales to the maximums of wavelet variance and entropy may make up the domain characteristic scale of NDVI, which is closely consistent with the regional topographical direction.