Combining Multiband Imaging, Photogrammetric Techniques, and FOSS GIS for Affordable Degradation Mapping of Stone Monuments

The detailed documentation of degradation constitutes a fundamental step for weathering diagnosis and, consequently, for successful planning and implementation of conservation measures for stone heritage. Mapping the surface patterns of stone is a non-destructive procedure critical for the qualitative and quantitative rating of the preservation state. Furthermore, mapping is employed for the annotation of weathering categories and the calculation of damage indexes. However, it is often a time-consuming task, which is conducted manually. Thus, practical methods need to be developed to automatize degradation mapping without significantly increasing the diagnostic process’s cost for conservation specialists. This work aims to develop and evaluate a methodology based on affordable close-range sensing techniques, image processing, and free and open source software for the spatial description, annotation, qualitative analysis, and rating of stone weathering-induced damage. Low-cost cameras were used to record images in the visible, near-infrared, and thermal-infrared spectra. The application of photogrammetric techniques allowed for the generation of the necessary background, that was elaborated to extract thematic information. Digital image processing of the spatially and radiometrically corrected images and image mosaics enabled the straightforward transition to a spatial information environment simplifying the development of degradation maps. The digital thematic maps facilitated the rating of stone damage and the extraction of useful statistical data.

The Potential of Optical Profilometry in the Study of Cultural Stone Weathering

The problem of deterioration of marble or stone monuments on display in the open air was raised in scientific terms around the mid-nineteenth century, correctly sensing the close dependence between the increased speed of surfaces alteration and air pollution. However, only more recently, around the years 1980–1990, emerged a need for quantitative data to assess the degree of degradation and the relative danger in the future projections. Non-destructive techniques can be an important aid in assessing the state of degradation and, above all, its speed, directly on the most important monuments exposed to the urban environment. In this work we discuss some non-destructive techniques able to evaluate the alteration of the surface shape of artefacts exposed to the environment through a non-contact survey of their surface shape. Advantages and disadvantages will be highlighted, as well as the problems still open.

Effect of Salt Crystallization on the Building Stones Used in Konya, Central Turkey

The cities of Konya, Kayseri, Ankara, Sivas, Kyrsehirand Nevsehir, all located in Central Turkey, are well-knownfor their famous historical buildings and monumentsbelonging to prehistoric to medieval civilizations. Withthe Hittite monuments and Seljuk-Ottoman mosques,medresses and caravansaries, the city of Konya is themost distinctive among others. Especially, the buildingsare significant for the identity of the Seljuk and Ottomanarchitecture, which was dominant during the period of11th and 20th centuries. Travertines, andesites and granitesare the most used rocks for construction purpose bythese two dominant empires in the Middle East. Thebuildings have suffered stone weathering since theirconstruction and the preservation of these buildingshas become a great issue for the past decades. The sourceregion of the rocks used in these buildings as well asHittite monument (dacite was used) at Eflatun is displayedin Fig. 1.