The research presented in this paper was carried out in the western part of Romania, on the administrative territory of Arad County, in Hălmagiu commune. The use of drones in the field of geospatial science is currently very demanding due to its relatively light operation and relatively affordable cost compared to satellite systems, especially high resolution images. In the last decade, the use of unmanned aerial vehicles as remote sensing platforms has become more and more popular for a wide range of disciplines and scientific applications. At present, many photogrammetric mapping methods have used drones to retrieve and record data on objects on the earth. Starting from the above considerations, the use of the drones in the "scientific exploitation" of the areas used as meadows is justified and appropriate. Conceptually and practically, this study seeks to quantify the process of reducing the useful area for feeding a meadow in time and space, using UAV technology and satellite imagery, by achieving three main objectives: Surface exploration through UAV technology, setting spatial-temporal evolution and cause-effect analysis. In the case of this study, a flight with the DJI Phantom 4 Pro equipment was performed, and the image processing was done with the Agisoft PhotoScan Professional software. The comparative analysis was done in the GIS environment, by overlapping and marking the negative changes occurring in the meadow analyzed over the course of four years. Between 2014 and 2018, the useful area of the analyzed meadow was reduced by 21.1%, from 5.83 ha to 4.60 ha, mainly due to two natural phenomena: the extension of the bushes and hence the afforestation and hydrological changes on the course of Crisului Alb, associated with erosion phenomena. Orthophoto and geospatial data from aerial photographs are particularly useful in other types of analysis: vegetation studies, topo-cadastral measurements, 3D modeling, land planning, hydrological studies, etc.

Unmanned Aerial Vehicle, flight planning, DJI Phantom 4 Pro, meadows, Google Timelapse

field crops and pastures

Presentation: oral