Evaluating UAVs vs. Satellite Imagery: A Case Study on Pistachio Orchards in Spain

Since the 20th century, satellites have been a mainstay in remote sensing. However, with the dawn of the 21st century, Unmanned Aerial Vehicles (UAVs) have emerged as pivotal remote sensing instruments across various sectors, notably in agriculture. Despite satellites and UAVs being complementary tools, they are often utilized without full comprehension of their implications. Precision agriculture, a field keen on maximizing productivity and efficiency, necessitates a clear understanding of the benefits and limitations of each technology, especially when applied to specific crops. This becomes paramount in the context of changing global climate patterns, where crops like pistachio are burgeoning in Southern Europe, notably in regions like Spain. Yet, the knowledge gap regarding the application of cutting-edge remote sensing technology in these crops remains significant. This study juxtaposes the use of satellite remote sensing, specifically Sentinel 2, with UAV remote sensing. This comparative analysis is conducted by evaluating agronomical parameters, such as vegetation indices, across two distinct pistachio orchards in Spain over multiple dates. Our findings highlight a discernible correlation between UAV and satellite data. However, satellite imagery consistently produced underestimations in variable values relative to UAV. This suggests that while satellite imagery might be apt for extensive crops, for woody plantations like pistachio orchards, UAVs present a more judicious choice. Leveraging UAVs can mitigate noise and provide more reliable crop-specific data, thereby ensuring more informed agronomical decisions.