Orthophoto of the Dorlay dam (Loire department), september 2020. Work made from 1826 aerial images taken by Aeromap Solutions, drone operator specializing in construction and technical inspections of engineering works. Post-processing by Drones Imaging.

On this structure, the orthophoto of the upstream facing (face facing south-west) allowed, by surface clipping, the georeferenced detection of all the disorders required by the specifications:

• Cracking.
• Construction joints.
• Crack <0.5mm.
• Crack >0.5mm.
• Patches.
• Beads.
• Geometric irregularities.

With variable surfaces, the polygons detected by photo-interpretation and sometimes overlapping each other on the upstream face, a calculation of the centroids made it possible to reduce the positive surfaces to unique geolocated points selectable by attribute class of disorders. Thus allowing, subsequently, to export an Excel workbook listing all the defects by class but also by location XYZ / NGF -General level of France thus offering the end customer a spreadsheet summarizing this inspection service for optimal management of their datas (as illustrated below).