A COMPARISON OF VEGETATION SPECTRAL INDICES DERIVED FROM LANDSAT 8 AND PREVIOUS LANDSAT GENERATIONS

摘要

The Landsat system has contributed significantly to the understanding of the Earth observation for over forty years. Since May 2013, data from Landsat 8 has been available online for download, with substantial differences from its ancestors, having an extended number of spectral bands and narrower bandwidths. This paper aims to examine how well Landsat 8 sensor perform its ancestors' vegetation observations, and more significantly, the differences between those of Landsat 8 and Landsat 5/7, hoping to optimize vegetation index continuity across different Landsat sensors. The paper investigates the quantitative relationship using regression analysis on the scatter plots of three indices derived from these sensors including the Normalized Difference Vegetation Index (NDVI), the Soil Adjusted Vegetation Index (SAVI), and the Urban Index (UI). Three scenes of Landsat 5, 7, and 8 images covering Hai Phong city, Vietnam was used. Comparisons indicate vague differences of vegetation indices derived from the sensors and their strong positive linear relationship, which supports the continuity of Landsat imagery use. Few notices are given as the NDVI and SAVI values in Landsat 8 appear to be higher than those of its ancestors, while the UI has relatively high correlation among the sensors despite in the water area.