## 2 Research Aims, Materials, and Method
### Methodology  
To provide the best possible answer to the query of _\"what are the most studied damages on cultural heritage across Europe and what are the technologies used\"_, our method was based on the assessment of the existing scientific and Grey literature. In this paper, however, we went a step further with an attempt to compare these two domains that could have very different final users (audiences). The main reason for this approach was the assumption that there could be some discrepancies in interdisciplinary interaction: while remote sensing scientists are not always fully aware of the needs of the cultural heritage sector, scholars involved in heritage study and preservation are not always up to date with recent technological advancements. In line with previous research [10], we felt that such a scenario might contribute to the divulgation of an unseemly narrative of the most relevant damages monitored using advanced technologies. In this respect, the focus of this paper is placed on the demonstration of the potential of advanced geomatics technologies, specifically on space-based solutions for a number of experts and non-expert end users, particularly in the field of archaeology and cultural heritage. The reason for this choice is that the information processed in the monitoring of damage to cultural heritage relies on different sets of data that are often managed in Geographical Information Systems, especially for extended areas or larger archaeological sites. Such complex sets of data must be organized, processed, and managed considering an appropriate representation of both the construction/monument/site and often its territorial surroundings. As the processing of such information increasingly requires an interdisciplinary and interoperable environment, we thought that geomatics technologies satisfy such requirements. As reviewed by [PERSON] [23], the term geomatics was based on the concept that the increased potential of electronic computing was revolutionizing surveys and representation sciences and that the use of computerized design was compatible with the treatment of huge amounts of data. Among the different geomatics techniques and disciplines able to assign a geospatial location to each object on the planet, we considered as a specific point of interest those of satellite-based remote sensing Earth Observation. Also, other technologies were taken into consideration because they are widely employed in (i) practices of heritage documentation and monitoring such as photogrammetry, laser-scanning, GPS, or RS ground sensor technologies and (ii) information management such as GIS and WebGIS. From the conceptual and methodological points of view, there are further reasons to include a dedicated analysis of the Grey literature. As observed in previous studies [12; 13], the scientific literature alone cannot provide an exhaustive representation of demonstration activities involving or made directly by users and stakeholders. Journal papers are mostly focused on applied research, methodological developments, and tests, as well as proof-of-concept or case studies; thus, it is sometimes unfeasible to grasp the real impact of RS and EO technologies on daily heritage practice. Moreover, policy, programmatic, and institutional documents issued by organizations and bodies in charge of heritage preservation are more likely to provide insights into the status of RS and EO technology uptake and embedding in operational workflows than journal papers. Hence, we have decided to act in two directions:  
1. To investigate the scientific literature that is a testimony not only to the base research but often to the applied research activities conducted during projects or pilot demonstrative initiatives;
2. To consider the Grey literature, i.e., materials and research produced and published in the form of reports, guidelines and white papers outside of the traditional academic publishing and distribution channels, catalogues, and repositories.