PHOTOGRAMMETRIC STUDY OF THE QUBBET EL-HAWA COPTIC CHURCH (ASWAN, EGYPT)
Keywords: Photogrammetry, 3D model, orthoimages, Coptic Church
Abstract. This paper presents the method applied and the results obtained in the photogrammetric study of the Qubbet el-Hawa Coptic Church. After several archaeological interventions, the ruins of this church were completely uncovered of sand. Therefore, a geometric documentation is justified in prevision of possible damages or deterioration that could affect it, considering the weakened status of several structures. In this context, we selected close-range photogrammetry because of the site conditions which include several vertical walls and occlusions that complicated the use of other terrestrial methods. In addition, a real texture of the object was demanded in order to obtain a complete documentation of the church. In this sense, some decorations and wall paintings were still visible causing this requisite of documentation based on real textures. However, the use of terrestrial photogrammetry was complicated due to the presence of occlusions, and in addition the use of Remotely Piloted Aircraft Systems (RPAS) was not allowed. So a method using a mast of about 4 to 6 metres was considered in order to lift the camera, avoiding these obstacles and reducing the amount of photographs needed. Applying this method, a great set of photographs was acquired and the scene covered with convergent images. The results of the photogrammetric processes were several metric products such as a 3D model with real textures, a ground Digital Elevation Model (DEM), several orthoimages, sections, etc. In addition a preliminary virtual reconstruction of the church has been developed based on these results. In conclusion, we have obtained a complete and reliable geometric documentation of the site and other derived products that can be used for other purposes. The method used has demonstrated its efficiency in these types of studies.