Proceedings 18 th International Symposium CIPA 2001 
Potsdam (Germany), September 18 - 21, 2001 
CLOSE RANGE PHOTOGRAMMETRY IN SUPPORT OF 
ARCHITECTURAL RESTORATION AND STRUCTURAL WORKS: 
A CASE STUDY 
Laura Baratin, Gabriele Bitelli, Marco Unguendoli, Antonio Zanutta 
DISTART - University of Bologna, Italy 
e-mail : laura. baratin@mail. ing. unibo. it, gabriele. bitelli@mail. ing. unibo. it, 
marco. unguendoli@mail. ing. unibo. it, antonio.zanutta@mail. ing. unibo. it 
KEY WORDS: Close Range Photogrammetry, 3D Database, Cultural Heritage, Restoration 
ABSTRACT 
In the framework of an extensive project for the survey of the fortification system and related historical buildings in Malta (“La 
Fabbrica delle Mura”), derived from a co-operation between the Maltese government and the University of Bologna, the Santa 
Caterina d’Italia church in Valletta, dated to XVII century, was the subject of a three dimensional complex surveying activity. Aim of 
the survey is to provide the information necessary for carrying out the complete restoration of the exterior, some restoration in the 
interior and structural works necessary for the church dome. 
During different campaigns the church was surveyed by means of topographic and photogrammetric techniques. 
The goal of the research is to build up a three dimensional database concerning the internal and external components of the church. 
Among the different applied analytical and digital methodologies, in the paper are mainly described the phase of digital orthophoto 
production to give metric and photographic description of dome’s frescoes, the stereoplotting of structural elements of the dome and 
the thematic 3D restitution of architectural elements on the façade. The work was carried out using different kinds of modern 
instruments and techniques, and some considerations related to their appropriate choice are presented. 
1. INTRODUCTION 
The classical way to perform an architectonic survey, principally based on direct measurement of the building's main structural 
elements integrated with theodolite observations, do not guarantees for the high accuracy required in restoration and engineering 
structural studies. Photogrammetry is the survey method that permits to obtain complete and accurate two- and three-dimensional 
products in vector and raster formats that fulfil the requirements of these applications; digital techniques, in particular, can provide 
high accuracy and varied products and applications at acceptable costs. 
Nowadays terrestrial laser scanning technology constitutes an innovative method to carry out 3D building’s survey and 
reconstruction. However, besides the very interesting and promising characteristics of this new technology, there are also some 
problems to be solved: it is not yet well defined the real accuracy of its products; error detection and removal procedures are not 
easy; the generation of a final product really usable in the restoration activities is not well defined and accepted; surface model 
generation for complex objects reveals some problems; finally, the cost for instrumentation and software is high.. 
The paper presents the surveying work carried out on the Santa Caterina d’ltalia church in Valletta, Malta (fig. 1), where 
photogrammetric and topographic techniques have been chosen and used for the full three dimensional survey of the building; laser 
scan could be an appropriate solution for some parts, but was not available at the time of the survey. 
Figure 1 : Santa Caterina d’Italia church before restorations