Photogrammetric evaluation options for ancient structures in Hypokremnos, Pagos, Paradiso and Nysa

Abstract

This study has focused on 3D reconstruction of ancient monuments based on photogrammetric documentation. The aim of the thesis is to search the limits of automatic and manual photogrammetric evaluation and modeling processes for interpreting of morphologic characteristics of ancient monuments with different geometries, positions, site conditions, and documentation necessities. Emphasis is made on documentation of historical structural characteristics for their conservation aim. In the methodology of the study, three parameters effecting the quality of the photogrammetric documentation are considered. First parameter is the type of the photogrammetric evaluation software. Manual photogrammetric software; Tgi3D SU and two automated photogrammetric software; Photosynth and Autodesk 123D are used in the study. Variation in the form, size and displacement of the monuments has been defined as the second parameter. In turn, four ancient monuments which have different characteristic features are studied; Hypokremnos Viaduct, Pagos Cistern, Paradiso Aqueduct and Nysa Library. Type of the 3D model and scale of documentation is defined as the last parameter of this thesis. A three dimensional way of documenting structural characteristics of ancient monuments is searched. 1/50 and 1/130 is selected for automatic documentation techniques as documentation scale, while 1/20 scale is selected for manual documentation technique. This study proves that documentation of structural characteristics of ancient structures may be realized in a successful way with manual photogrammetric technique. The 3D model is much more satisfactory compared to those based on automatic photogrammetric techniques in terms of accuracy control, level of geometric detail and documentation of surfaces. Consequently, while automatic evaluation is insufficient for providing data leading to structural evaluation, manual photogrammetric evaluation enriches the content of documentation of a historical structure. Structural system detail and 3D model to be used in intervention decisions of structural system can be produced with the help of the manual photogrammetric technique without the necessity of any further documentation.