Proceedings 18 th International Symposium CIPA 2001 
Potsdam (Germany), September 18 - 21, 2001 
THE “DEMOCRATISATION” OF PHOTOGRAMMETRIC ARCHITECTURAL SURVEYS 
Georges Abdelnour 
Architecte D.P.L.G. / Technical Director 
TRIMENSIONS s.a.r.l. 
20, rue Félicien David - 75016 Paris, France 
Phone : +33-1 45 24 24 54 ; E-mail : mail@trimensions.fr 
KEY WORDS 
Close-Range Photogrammetry, Architectural Surveys, Monuments Historical, Cultural Heritage, Architectural Archiving, Urban 
Estate Management, 3D Survey 
ABSTRACT 
In spite of the progress achieved in the field of Photogrammetry and Remote Sensing (equipment, instruments, hardware and 
software) and the growing need for setting up architectural databases, the offer does not meet the demand. Photogrammetry is still 
regarded as a heavy, sophisticated and costly technology that could be implemented only for a few prestigious sites. 
With progress in photogrammetric equipment, data obtained through the measuring or the scanning stage is more and more 
exhaustive. More information means higher process requirements, longer procedures and higher costs. 
The solution is obviously the correct selectivity of data (acquired and processed) for the optimal achievement of graphical 
representations exactly in accordance with the specific requirements of end-user. 
This procedure was set-up and experimented successfully on many sites without any compromise on quality or accuracy. 
With this TRIMENSIONS photogrammetric process, the following sites were surveyed: 
• Carrés Saint-Louis in Versailles (France) : rehabilitation project, 5 weeks, 4 operators; 
• Cagliari down-town (Italy) : architectural archiving, 14 weeks, 4 operators; 
• Beirut 1/3 down-town (Lebanon) : reconstruction project, 12 weeks, 5 operators. 
1. NEEDS AND EMERGENCY 
Earth photogrammetry applied to architecture is a true need today, and no more a luxury reserved to a few prestigious operations. 
Needs are real, in fields of archiving, conservation of threatened properties, in rehabilitation studies, in modern town management, 
studies of urban impact of new building projects, etc... 
Nowadays, official institutions such as “Monuments Historiques”, “Town facilities Services”, as well as architects and town 
planners, all have access to a wide array of information of all types : geographic, cadastral, topographic, technical, ... and are 
equipped with 3D computer software and systems. However, what they lack are architectural surveys compatible with their 
equipment ; thus the fundamental missing link to the urban estate management softwares is the knowledge of three-dimensional data 
of buildings. 
The demand is pressing and only the technique of earth photogrammetry is able to meet these needs. The only drawback to the 
démocratisation of architectural photogrammetry is that of cost, which in turn is directly related to time of execution. 
2. TOWARDS SOLUTIONS 
2.1 Optimisation leads 
In order to circumvene the obstacle of cost and open photogrammetry to the market, the technical team of TRIMENSIONS has 
optimised certain procedures in the various steps of work. This has allowed undertaking surveys that are to the scale of a whole town, 
with execution delays and costs comparable to those of traditional architectural surveys. 
Among the numerous used optimisation procedures, we will give a few examples related to each step of the work: