The Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Vegetation Indices (MYD13Q1) Version 6 data are generated every 16 days at 250 meter (m) spatial resolution as a Level 3 product. The MYD13Q1 product provides Normalized Difference Vegetation Index (NDVI) which is referred to as the continuity index to the existing National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) derived NDVI. The algorithm chooses the best available pixel value from all the acquisitions from the 16-day period. The criteria used is low clouds, low view angle, and the highest NDVI value.

Reference: LP DAAC - MYD13Q1 Version 6