The normalized difference vegetation index (NDVI) has been commonly used for vegetation monitoring, such as water stress detection, crop yield assessment, and evapotranspiration estimation. However, the influence of spatial resolution on the individual tree level NDVI using the Unmanned Aerial Vehicles (UAVs) is poorly understood. Therefore, in this research, the effects of the spatial resolution of UAV imagery are investigated using high-resolution multispectral images. A temporal sequence of UAV multispectral imagery was collected over an experimental pomegranate field, capturing variations in the whole growing season of 2019, at the USDAARS (U.S. Department of Agriculture, Agricultural Research Service) San Joaquin Valley Agricultural Sciences Center in Parlier, California, USA. The NDVI distribution of individual trees was generated at the 60 m, 90 m, and 120 m spatial resolution. Experimental results indicated how the spatial resolution of UAV imagery could affect NDVI values of individual trees.
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