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Drones in Agriculture: Soil Fertility and Crop Management
Published in K. R. Krishna, Push Button Agriculture, 2017
In the Texas High Plains, so far, aerial imagery from piloted aircraft and satellites has proved useful to detect and judge general vegetation. Crop production zones are also studied using such aerial surveys. However, crux of the situation in farming zones is that aerial imagery that detects and differentiates cotton farms and natural vegetation is necessary. The cotton farms are affected by volunteers and boll weevil. Therefore, imagery using drones that fly low above the crop, that helps to detect insect attacked areas and identifies weeds/volunteers is very useful. Both ground-based and drone supplied multi-spectral reflectance data could be processed to arrive at accurate spray schedules and volunteer culling programs. Hoffman (2013) states that if multi-spectral data from drones or other sources are not used, cotton plants affected with Boll weevil may actually be overlooked. The spectral signatures of healthy cotton plants, and boll weevil affected plants has to be identified correctly.
Construction of high-precision DEMs for urban plots
Published in Annals of GIS, 2023
Min Li, Wen Dai, Susu Song, Chun Wang, Yu Tao
Usually, urban DEM modelling is completed by the interpolation of elevation data obtained from field measurement (Yonezawa 2009; Guonian et al. 2017; Li et al. 2022; Xiong et al. 2022), digitization of topographic maps (Chi and Song 2004; Wenshuang, Haili, and Fei 2008), LiDAR point clouds (Cui et al. 2013; Xiaoxia 2021; Hui et al. 2009; Xiaochun 2020a; Du et al. 2021), photogrammetry and remote sensing and multi-source data (Minqiu, Wei, and Wei 2009; Wang, Sun, and Xiaojuan 2016; Fachang and Wangmin 2019). Research of high-precision urban DEM modelling focuses on the data acquisition and process, and then the methods of generating TIN or interpolating DEM are still adopted. The first three kinds of data acquisition have their disadvantages, such as being time consuming, laborious and high cost. The fourth data acquisition of generating DEM by digital automatic photogrammetry has high automation, fast processing speed, and high map accuracy. This kind of production method is more extensive and the technological route is more mature and the cost is also lower. The unmanned aerial vehicle (UAV) photogrammetry technology is one of the digital photogrammetric methods, and greatly reduces the manual field workload, improves the efficiency of acquiring geographic information data and makes it possible to acquire high-precision terrain data in the region quickly. High-resolution Digital Orthophoto Maps (DOMs), dense point clouds and real sense 3D models based on image-intensive matching data can be obtained by UAV aerial survey technology, which has been used increasingly in the research of digital elevation model construction (Xiaoyi and Luhe 2017; Jing et al. 2022; Zhuohao 2022).