The construction of the underground station called Place des Martyrs in Algiers required preventive excavation. The context led us to favour recording methods leading to the rapid and exhaustive acquisition of data. Indeed digital photogrammetry made it possible to measure complex elements simply and rapidly. The originality of the solution implemented resided in the use of a free and open-source applications suite dedicated to scientific usage and making it possible to generate 3D models similar to those obtained by lasergramme-try. More than 1500 shots were acquired during this first measurement campaign. Plans and sections were extracted on request from the scatter plot. Tacheometric survey operations were reduced to measuring only control points required for geo-referencing images. The digital photogrammetric survey of such a volume of remains in a preventive archaeological context in an urban environment is to our knowledge unique. The importance of this case study also resided in the use of a fully free and open-source professional applications suite. In the end, this method could be used regularly on other similar excavations.