Evaluating Unmanned Aerial Vehicles vs. Satellite Imagery: A Case Study on Pistachio Orchards in Spain

Abstract

Since the 20th century, satellites have been key in remote sensing, but the 21st century saw the rise of UAVs, especially in agriculture. While both are vital tools, their implications are often misunderstood. Precision agriculture requires an understanding of its strengths and weaknesses, especially with changing climate patterns affecting crops like pistachio in southern Europe. This study evaluates the effectiveness of satellites and UAVs in measuring NDVI for pistachio orchards in Spain, utilizing Sentinel 2 and a UAV equipped with a MicaSense Altum sensor. The results show that satellite data consistently underestimated NDVI values compared to UAV data, with a correlation of r-values ranging from 0.65 in July to 0.71 in September. The correlation values were consistent and very similar in all orchards. Despite the underestimation, satellites are deemed suitable for broader trend analysis, while UAVs provide more granular, precise agronomical assessments. An integrated utilization of both technologies is recommended for comprehensive and accurate precision agriculture practices.

Keywords

• remote sensing
• unmanned aerial vehicles (UAVs)
• satellite imagery
• precision agriculture
• pistachio orchards
• Sentinel 2