SAVI (Soil Adjusted Vegetation Index) image of central Arizona-Phoenix from a 1990 Landsat Thematic Mapper image

Normalized difference vegetation index (NDVI) produced from the 1990 Landsat Thematic Mapper(TM) image. NDVI is a means of monitoring density and vigour of green vegetation growth using the spectral reflectivity of solar radiation.归一化差分植被指数（Normalized Difference Vegetation Index，NDVI）由1990年陆地卫星（Landsat）专题制图仪（Thematic Mapper，TM）影像生成。该指数是一种利用太阳辐射的光谱反射率，监测绿色植被生长密度与活力的方法。