The MODIS Terra MOD13A1 Version 6.1 product provides Vegetation Index (VI) values at 500 m spatial resolution on a per-pixel basis. The dataset includes two primary vegetation indices: the Normalized Difference Vegetation Index (NDVI), which serves as a continuity index with NDVI derived from NOAA-AVHRR observations, and the Enhanced Vegetation Index (EVI), designed to improve sensitivity in regions with high vegetation biomass. The product is generated as a 16-day composite, where the algorithm selects the best available pixel from all acquisitions within the compositing period based on criteria such as low cloud contamination, low view angle, and the highest NDVI/EVI value. Along with the vegetation index layers, the product includes two quality assurance layers, reflectance bands 1 (red), 2 (near-infrared), 3 (blue), and 7 (mid-infrared), as well as four observation layers.