Renovation of the GMK Stadium, Cotonou

The context

GMK Stadium (Général Mathieu Kérékou) is Benin's national stadium, hosting the national team's international matches. Its renovation to FIFA standards, led by Gregori International, included complete pitch rework, stands, technical installations and perimeter security. The project lead wanted exhaustive geolocated weekly site monitoring, usable both internally to steer progress and externally to report to funders and sports federations.

Our method

Weekly high-resolution photogrammetric flights over the stadium and its surroundings, across an 18-month period. Layout of fixed RTK GCPs to guarantee geometric comparability between all successive campaigns. Simultaneous RGB and 4K capture for the video report. Standardised processing: orthophoto + 3D model + comparison vs previous week. Tight coordination with the site director and HSE manager to adapt flight windows to sensitive phases (concrete pouring, load handling, welding).

What we delivered

• Weekly photo/video reporting (PDF + web gallery)
• Centimetric orthophoto of each campaign (GeoTIFF)
• Textured 3D model of the site at each contractual milestone
• Documentation of critical phases (earthworks, structure, finishes)
• Quality control via model comparison between campaigns
• Progress videos shareable with funders
• Georeferenced as-built plan at site close-out
• Centimetric archive of the structure for future maintenance

The outcome

Gregori International had an objective, quantified steering tool throughout the works. Schedule deviations vs the plan were detected in near real time, enabling fast arbitrage. The final report, including the complete centimetric archive of the structure, became a preventive-maintenance tool for the post-handover manager. The methodology has been replicated on other group sites.