Stereo-orthoimage as a GIS tool for reliable restitution of Cultural Monuments

摘要

The use of photogrammetric techniques for the geometric documentation of monuments and archaeological sites is widely known and applied. The basic techniques are: (a) the stereo-restitution, which provides the advantage of 3D observation and accurate digitization but requires specific photogrammetric knowledge and equipment, and (b) the orthophoto, an easy to use raster product that enables the 2D digitization, which is, however, not sufficient for monuments that consist of complex surfaces. The concept of stereo-orthoimage was firstly introduced at the end of the 1960s for cartographic and cadastral applications, combining the advantages of both the orthophoto and 3D observation. This paper analyses the algorithms used for the generation of stereo-orthoimages, presents a developed plugin for the free open-source Geographic Information System QGIS that implements the stereo-orthoimage technique and examines the use of this technique for the restitution and digitization of complex surfaces of monuments for their large scale geometric documentation. The QGIS plugin, named OrthoStereoMate (OSM), has been developed in the Python programming language and will become freely available to the official python plugin repository for QGIS users.