The first step in the process of restoring a monument is an exact geometric documentation. The photogrammetry is one of the fastest methods of geometrical surveying documentation, used by very early recording of monuments, historical buildings and complexes.
The introduction of digital photogrammetry techniques in recent years, brought about significant changes in the final deliverable and resulted in the gradual replacement of line drawings of figurative products, ie orthofotomosaics and 3D models with textures, which are now standard photogrammetric deliverable, especially for surveying archaeological sites and monuments.
This is almost obvious: combine the geometric accuracy of the project with the visual - qualitative information of the photo. Thus, the final interpretation and specialized design characteristics of the object by the final recipient, the architect, the archaeologist, the civil engineer, the restorer.
Certainly the production of orthophotos, archaeological documentation for purposes other than the large scale of the final product presents important peculiarities, arising mainly from the morphology and complexity of the object's shape, location (eg, difficulty of access) and usually by extremely low-budget studies of this kind.
For all of the Athenian Acropolis hitherto available data were insufficient. The main problem was that existing surveys were limited and variations in accuracy. Especially on the hill and the wall, the traditional methods failed to give the desired results, mainly due to the size of the monument, the difficulty of access, steep terrain and the constant presence of visitors. To solve the problem required photogrammetric surveys, coupled with three-dimensional scanning.
To capture the hill and the Walls YSMA designed the project "Development of Geographic Information Systems at the Acropolis of Athens", financed by the OP "Information Society".
In addition to the requirements of ongoing work in areas where the monuments executed or will execute restoration interventions are developed by individual service photogrammetric studies (at scales 1:10 and 1:20).