SATELLITE INDICES IN VEGETATION DESCRIPTION - COMPARATIVE ANALYSIS AND INTERDEPENDENCES

Abstract

The study analyzed the variability of some indices, interdependence relationships and differences in the vegetation description. Based on the Rapid Eye satellite system, images were taken for the ATU Padureni area, Timis County, Romania. From the analysis of the images, the spectral bands were obtained and the NDVI, gNDVI, NDVIre, and RTVIcore indices were calculated. The series of values presented a normal distribution, under conditions of r = 0.982 in the case of gNDVI, r = 0.961 in the case of NDVI, r = 0.983 in the case of NDVIre, respectively r = 0.990 in the case of RTVIcore. The descriptive statistical analysis facilitated obtaining the values of the statistical parameters and the description of the data series for each index. Based on the coefficient of variation (CV), the indices considered showed high variability; CV = 54.7535 in the case of the NDVIre index, CV = 57.2578 in the case of the RTVIcore index, CV = 58.0955 in the case of the NDVI index and CV = 64.5481 in the case of the gNDVI index. Linear models described the variation of the gNDVI index and the NDVIre index in relation to the NDVI index (p = 0). Polynomial models of the 2nd degree described the variation of RTVIcore in relation to NDVI (R2 = 0.918), in relation to gNDVI (R2 = 0.954) and in relation to NDVIre (R2 = 0.938), p = 0. The comparative analysis of gNDVI and NDVIre indices in relation to NDVI led to statistically significant differences (p<0.001) in relation to the mean and median value of the NDVI index.