The survey of archaeological sites, monuments, traditional edifices, historic centres and settlements, is a prerequisite for every archaeological, historical and architectural study as well as for any project on their protection, preservation and promotion. The survey process in all aforementioned cases requires the application of scientific methods of exceptional precision and the employment of modern technology in the relevant sector. However, the survey procedure varies as regards the thematic presentation and precision and depends on the object and purpose of the survey. Therefore, we distinguish:
a. The analogical method which is based on the use of infinite points and can achieve excellent surveying results, without the support of any other procedure.
b. The analytical method which is based on the definition of a limited number of points which, if united, produce the form of the object. Protogrammetry meets the demands of the first method, while the science of geodesy, topography, chartography and photogrammetry serve the needs of the second.
In this article the topographical and photogrammetric methods are mainly analysed.
The thorough study of monuments also demands the definition of their structural distortions, so that their pathology can be studied and necessary treatments be proposed. The relevant measuring aims at
a. Defining the extent of the actual distortion.
b. The observation and documentation of a building through time.
The application of topographical and photogrammetric methods gives in both cases satisfactory results; the second case demanding high standards of precision. Furthermore, the contribution of networks for observation of micro-deplacement of constructions as well as the analytical photogrammetric methods is very important. The photogrammetric archives, which include measurements and photogrammetric exposures are, undoubtedly, the best organized archives of monuments. They offer full documentation of the monuments through time and guarantee their exact recording in case of any future destruction, which may be caused by a variety of reasons.