Creating a true orthophoto involves a series of steps to ensure that the resulting image provides a true top-down view, free from any perspective distortions, including the correction of terrain relief, camera angles, and building lean. Here's an overview of the process: ✅1-Aerial Image Acquisition: Aerial imagery is captured using specialized cameras mounted on drones. These cameras capture images of the area of interest from different angles and altitudes(with 80% frontcoverage and 60% side coverage or more). ✅2-Image Preprocessing: Raw images are preprocessed to correct for lens distortion, vignetting, and other optical aberrations. This step is crucial to ensure the accuracy of subsequent processing. ✅3-Photogrammetric Processing: Photogrammetry is used to determine the spatial relationship between the images and the ground. This involves identifying common features in multiple images (tie points) and using these to calculate camera positions, orientations, and a point cloud representing the terrain. ✅4-Digital Surface Model (DSM) Generation: A Digital Surface Model is created using the point cloud data, which represents the Earth's surface including buildings, vegetation, and terrain relief. ✅5-Digital Terrain Model (DTM) Generation: The Digital Terrain Model represents the bare Earth surface without buildings and vegetation. It's derived from the DSM by filtering out structures and other above-ground features. ✅6-Orthorectification: The orthorectification process corrects the image for relief displacement by using the DSM and DTM. Each pixel in the image is transformed to its true ground position, removing the effects of terrain and camera perspective. ✅7-Building Vectorization: Using the orthorectified imagery and additional processing, buildings and other vertical features are detected and vectorized to create accurate building footprints. ✅8-True Orthophoto Generation: The orthorectified imagery is further processed to create a seamless true orthophoto. This involves blending and combining the orthorectified images while ensuring that building facades and other vertical features are removed, resulting in a true top-down view. ✅9-Quality Assessment: The final true orthophoto is rigorously evaluated for accuracy, completeness, and visual quality. Any remaining distortions or inaccuracies are addressed and corrected. 🔍Specialized software and expertise in photogrammetry, remote sensing, and geospatial analysis are critical for successfully creating high-quality true orthophotos. Additionally, accurate ground control points, precise camera calibration, and quality aerial imagery are essential components of this intricate process.