12/05/2026
A Rectified Orthophoto of 0.3m. Achieving a ground sampling distance (GSD) of 0.3 meters in orthophoto production involves meticulous integration of field data acquisition and photogrammetric processing. Data acquisition entails establishing Ground Control Points (GCPs) observed using static GNSS surveying with high-precision receivers for accurate georeferencing within the project coordinate system. Aerial image capture is conducted with a flight configuration designed to meet spatial resolution and coverage requirements, utilizing 75% forward overlap and 65% side overlap for robust image matching and 3D reconstruction. The UAV (DJI Phantom 4 RTK) is flown at a controlled speed of 4 m/s to minimize motion blur, with a gimbal angle of -90° ensuring vertical image acquisition. Photogrammetric processing involves standard digital workflows, including image alignment, tie point generation, bundle adjustment with GCPs, dense point cloud generation, and Digital Surface Model (DSM) derivation. Orthomosaic generation is performed by stitching geometrically corrected images, removing distortions caused by terrain relief and camera tilt, resulting in a uniform-scale, high-resolution image with 0.3 m spatial resolution. The final rectified imagery ensures all spatial features are correctly positioned according to the chosen coordinate reference system, making the dataset suitable for mapping, analysis, and engineering applications. This workflow ensures high positional accuracy, consistency, and reliability of the final geospatial products.