Remote sensing technology has become a vital tool for scientists over the past several decades for monitoring changes in land use, ice cover, and vegetation across the globe. Satellite imagery, however, is typically available at only coarse resolutions, allowing only for the analysis of broad trends over large areas. Remote-controlled drones are an increasingly affordable alternative for researchers working at finer scales in ecology and agriculture, but the laser-based technology used to estimate plant productivity and biomass, such as light detection and ranging (LiDAR), remain prohibitively expensive.
source https://phys.org/news/2021-02-drone-based-photogrammetry-reliable-low-cost-method.html
