Space based platforms are an important source of information for the conservation and protection of cultural heritage. The International Council on Monuments and Sites (ICOMOS), a leading international organisation with strong links to cultural heritage conservation utilising space-based resources, will introduce its endeavours.

ICOMOS works to conserve and protect cultural heritage places. It is the only global non-government organisation of this kind, which is dedicated to promoting the application of theory, methodology, and scientific techniques to the conservation of the architectural and archaeological heritage. ICOMOS is a network of 11 000 experts that benefits from the interdisciplinary exchange of its members, among which are architects, historians, archaeologists, art historians, geographers, anthropologists, engineers and town planners. The members of ICOMOS contribute to improving the preservation of heritage, the standards and the techniques for each type of cultural heritage property: buildings, historic cities, cultural landscapes and archaeological sites.

ICOMOS’ International Scientific Committees, partner organisations, associated academic institutions and many of its members are actively utilising data from space-based platforms to undertake research into the impacts of climate change; human activity, ranging from urban development to armed conflict; and to undertake archaeological and other heritage-related research.

Among the main actors is the ICOMOS / ISPRS Committee for Documentation of Cultural Heritage, CIPA Heritage Documentation, an international non-profit organisation that endeavours to transfer technology from the measurement and visualisation sciences to the disciplines of cultural heritage recording, conservation and documentation. CIPA thus acts as a bridge between the producers of heritage documentation and the users of this information. The ability to monitor heritage from space has proved to be a powerful tool in heritage management.

The ICOMOS International Committee on Risk Preparedness (ICORP) enhances the state of preparedness within the heritage institutions and professions in relation to disasters of natural or human origin. It promotes better integration of the protection of heritage structures, sites or areas into national, local as well as international disaster management, including mitigation, preparedness, response and recovery activities. By sharing experience and developing a professional network, ICORP aims to stimulate and support activities by ICOMOS National and International committees for enhancing disaster risk management of cultural heritage. ICORP also supports ICOMOS in its role as the founding partner of the Blue Shield. Data from space-based platforms is an integral aspect of heritage risk preparedness, analysis and response.

This presentation, by a range of experts from ICOMOS, will offer an overview of how space-based monitoring of cultural heritage is now integral to enhancing, better protecting and conserving humanities’ rich and diverse cultural heritage. Scientists, engineers, historians, heritage practitioners, scholars and social scientists are encouraged to attend this session to gain information, establish and enhance their networks, and explore future collaborations.

Background
This work assesses the suitability of a range of satellite imagery for a) detection of buried archaeological and cultural heritage sites; b) monitoring the condition of known archaeological assets; and c) land-use assessment on a national scale. This contributes to a broader ambition to assess remote sensing methods for national-scale survey and heritage management [1]. Over the last couple of decades, satellite data has been reliably used in archaeological site detection and monitoring [2, 3], primarily in arid regions. The climate and weather conditions, land-use and nature of cultural heritage sites in Scotland and Northern Europe make these regions challenging to assess using similar methods [4].
The available satellite data was assessed for frequency of coverage, the ease and accuracy with which proxy indicators of archaeological features (such as crop and soil marks) could be identified, and the ease and accuracy with which land-use changes which have particular implications for cultural heritage sites could be determined. Scotland was used as a trial region, with the understanding that the developed methodology could be applied to other regions with similar climate, land-use and geology.
Satellite data was supplied by the European Space Agency and Planet Labs Inc. Optical data was provided for a variety of regions of interest across Scotland at ground sample distances (GSDs) of 0.5-3m. All imagery was collected in the spring and summer months (April – July) of 2018 and 2020. Particularly dry summers in these years produced high numbers of crop proxies in Scotland. The distribution of data across the spring and summer months was selected to allow for a comparison between imagery to be made over this summer period.

Data Availability
The available data was evaluated to consider the frequency with which suitable data could be reliably acquired of the regions of interest. This process included both automated filtering of the data, and manual examination of the imagery. Data was considered unfit if it did not cover a sufficient proportion of the area of interest, or if it was too cloudy to produce a clear image. Considering all available imagery, approximately 15% of available images were found to be useable. This included imagery that was collected in response to direct tasking requests [5]. Additionally, the usable images were often collected within narrow time periods (e.g. the same or subsequent days) making them unsuitable for prospection methods relying on crop mark identification and limiting their value in both change detection and condition monitoring.

Data Suitability
All the imagery proved suitable for broad brush landscape assessment. Using the data with < 1m GSD an experienced photo-interpreter could visually identify vegetation type and general landscape characteristics. However, the reduced resolution in off-nadir images can make the interpretation challenging. For imagery with > 1m GSD, confidence in interpretation diminishes.
For monitoring the condition of designated ancient monuments, the < 1m GSD imagery provided adequate generalised views of vegetation cover, which can be a good proxy for condition. However, the satellite imagery, even at its best in a nadir view, does not have the resolving power required to identify specific items of concern, such as discrete areas of rabbit burrowing.
For identification of monuments, the < 1m GSD data has proved to be adequate for detecting variation in vegetation down to c. 1m across. However, with many of the archaeological features commonly found in Scotland often being ≤1m, the resolution of the imagery puts it on the cusp of reliably resolving such features.

Conclusions
The available satellite data has the potential for use in historic environment applications including land-use assessment, condition monitoring, and archaeological prospection. Datasets with < 1m GSD are of significantly higher value compared to data with > 1m GSD; the reliability and confidence with which the latter could be used for all proposed applications was notably lower than the former. However, the intermittent availability of suitable imagery is a significant limitation. Although the presented work focuses on Scotland as a case study region, it is expected that the outcomes would apply across regions of similar climate across Europe. Were < 1m GSD satellite data available to the European historic environment community with suitable frequency and reliability, it could be of significant value.

References
[1] Banaszek, Ł., Cowley, D. C., & Middleton, M. (2018). Towards national archaeological mapping. Assessing source data and methodology—A case study from Scotland. Geosciences, 8(8), 272. doi: https:// doi.org/10.3390/geosciences8080272
[2] Lasaponara, R., & Masini, N. (2011). Satellite remote sensing in archaeology: past, present and future perspectives. Journal of Archaeological Science, 9(38), 1995-2002. doi: 10.1016/j.jas.2011.02.002
[3] De Laet, V., Paulissen, E., & Waelkens, M. (2007). Methods for the extraction of archaeological features from very high-resolution Ikonos-2 remote sensing imagery, Hisar (southwest Turkey). Journal of Archaeological Science, 34(5), 830-841. doi 10.1016/j.jas.2006.09.013
[4] Cowley, D. C. (2016). Creating the cropmark archaeological record in East Lothian, southeast Scotland. Prehistory without Borders: Prehistoric Archaeology of the Tyne-Forth Region; Crellin, R., Fowler, C., Tipping, R., Eds, 59-70.
[5] McGrath, C. N., Scott, C., Cowley, D., & Macdonald, M. (2020). Towards a satellite system for archaeology? Simulation of an optical satellite mission with ideal spatial and temporal resolution, illustrated by a case study in Scotland. Remote Sensing, 12(24), 4100. doi: 10.3390/rs12244100

The region of eastern South Africa plays a major role in the development of the technical and behavioural capacities, that allowed Homo sapiens to expand into Europe and Eurasia during the Late Pleistocene. Although the region yields some of the best-studied archaeological sequences, it is still understudied in terms of site density and open-air sites, which could help to better understand the connectivity and use of space of ancient populations. We present two applications of remote sensing for archaeological prospection, that are tailored for the specific detection of (a) open-air sites and (b) rock shelters.
Colluvial landforms are suitable archives as they preserve archaeological artefacts bedded in sediment layers that provide context information on past landscape stability, climate and vegetation changes and allow radiometric dating methods. We mapped these landscape features through the use of multispectral remote sensing and digital landscape analysis. The spectral properties of local surface and soil profile materials were characterized in situ through field spectroscopy (250-2500 nm wavelength), yielding high resolution reflectance curves that give insight to their physio-chemical properties. Thereupon we developed spectral indices, which enable the discrimination of different surface types and applied these to VIS, NIR and SWIR bands of WorldView-3 to map the colluvia based on its specific spectral properties.
Rock shelters host most of the currently known archaeological sites of the region, where excellent preservation conditions allow to study millennia old anthropogenic remains with resolutions of centuries and even decades. We predicted the presence of potential sites through the analysis of a high accuracy DEM (TanDEM-X). The application of geomorphometric and hydromorphometric indices together with stratigraphical information allowed to derive the specific properties of this landform.
Our results show a large number of yet unidentified potential archaeological sites of both types. They lay a foundation for a DFG-funded project starting 2021 (WI 4978/3-1), that will evaluate the results in a interdisciplinary framework of researches from domains like archaeology, geography, geology, chronometry, paleoproteomics, biogeology, etc.

Over the last two decades remote sensing of satellite imagery for cultural and natural heritage (CNH) risk assessment has significantly increased. Corroborating evidence of such a growth of interest is found in the scientific publications, white papers, policy documents and more generally in the grey literature. At the same time, protection and safeguarding of cultural and natural heritage have been raised higher in international agendas (e.g. as a target in the UN SDG #11) and what satellite technologies can specifically do towards this scope is the subject of reflections at least at European level (e.g. Copernicus Cultural Heritage Task Force).
Despite these major advances, the majority of studies focused on selected types of damages such as looting, natural-hazards and conflicts-related that were generally deemed as the most dangerous ones (Zaina 2019) or that were more consistently covered by the increased flow of information and media attention in response to the events occurring in different regions. This narrative has been recently tackled by studies asking for a more comprehensive understanding of the entire set of damage to CNH. In particular, they shed light on other equally or more dangerous but under-considered threats including ploughing, construction of roads and buildings or even large infrastructures. Among the latter, the construction of dams resulted in the flooding of thousands of archaeological sites in different places of the world. Despite this pervasive effect, specific regulations, as well as tailor-made methodologies to document and monitor this type of damage, are yet to be codified (Marchetti et al. 2020).
Current counteractions are spotty and suffer from a lack of coordination by international and national authorities, while support from ad hoc legislations is also missing in many countries. Moreover, mitigation strategies – e.g. activities of rescue archaeology that the present paper aims to target as a specific application domain for which satellite data may be a useful support for archaeologists in areas of dam construction – mostly rely upon ground-truthing activities and, in some cases, aerial imagery. The limits of these strategies include: 1) incomplete research methodology, which does not consider the potential of remote sensing for sites identification; 2) limited timeframe, as ground-truthing allows only to identify the latest types of damages that are visible at the time of in-situ surveys; 3) incomplete geographic coverage, as confirmed by many archaeological surveys in prospective reservoir dams; 4) low level of detail, as ground-truthing does not allow to appreciate anomalies visible for space.
These shortcomings could be effectively overcome by integrating remote sensing of satellite imagery. It is, in fact, well-known that archaeological research methodologies are highly benefitting from the growing availability of open-access satellite imagery and their accessibility through different online platforms like Google Earth and Bing Maps (Agapiou 2017), thus opening new research avenues, including their application for archaeological damage assessment and monitoring. However, what open data from Copernicus Programme, as well as licensed data from Contributing and Third Party Missions, can do in the context of dams construction has not been fully explored yet. Furthermore, the use of satellite data is not yet an established practice across the archaeology community.

In this context, this paper aims at showing the potential of multidisciplinary collaboration between image analysts and archaeologists to carry out activities of site documentation from remote for rescue archaeology, by which Copernicus Programme Sentinels and Contributing Missions data are integrated to assess the impact of dams on cultural heritage. Building from the three protocols system proposed by Marchetti et al. (2020), we focus on how satellite imagery can input into the first protocol, named Pre-Construction Archaeological Risk Assessment (PCARA), consisting in the quantification of archaeological evidence located within the prospective reservoir area before dam construction and/or when impoundment/reservoir filling takes place. The integrated methodology encompasses the following steps:
1. Reconstruct dam construction/impoundment timeline and identify user needs (e.g. documentation prior to flooding and loss vs. assessment of residual risk in case partial damage or loss already happened);
2. Search for baseline data to check whether inventories of sites at potential risk are already available or an ex-novo site survey is required;
3. Search for archive satellite imagery matching the temporal framework of dam construction and identify user requirements for new imagery collection to perform change detection and time series analysis;
4. Task satellites accordingly or make an informed selection of routinely collected imagery, also accounting for variables on the ground that may impact the quality of the observations;
5. Manual surveying conducted by archaeologists with expertise in site identification and good background in remote sensing (the latter being an advantageous skill, that may be also built during the collaboration and support from the image analysts);
6. Site mapping and risk assessment, with iterative process back to satellite data selection and/or new image acquisition repeated, better or refined satellite observations are needed.
Ideally, this workflow should be completed with validation in the field through ground-truthing, that is however beyond the scope of this presentation.
We showcase the feasibility of this methodology on two case studies, the small planned dam of Halabyeh in Syria and the large, currently under construction Grand Ethiopian Renaissance dam.
The first case is an arid region poorly covered by archive satellite imagery. Therefore, besides the use of already available open access dataset, a robust acquisition strategy of imagery was required to integrate the dataset. To this aim, we tuned the satellite acquisition schedule by programming the full Italian Space Agency’s COSMO-SkyMed constellation to collect high-resolution SAR images to meet the needs of archaeological research.
In the second case, we chose a humid region well documented by both SAR (COSMO-SkyMed) and multispectral imagery (Sentinel-2) prior to the reservoir filling. The temporal acquisitions collected over this area by different satellites cover both low and high vegetative periods.
One of the main lessons learnt specifically regards step 4. In order to achieve the most accurate site identification, it is essential to consider the following two types of variables that can influence the detectability of an archaeological site: 1) temporal; 2) environmental.
The temporal variable relates to the timeframe of the dam construction and how satellite data can provide sufficient temporal coverage of the different phases (i.e. pre-, during and post-construction). Therefore, this variable influences the selection of the archive and new images to be acquired. In particular, in the case of an area with few archive images, a new acquisition campaign has to be carried out.
The environmental variable regards the physical properties of the natural setting where the dam is constructed that affect the visibility of archaeological features in the satellite data. Above all, seasonality. Indeed, highly vegetative landscapes may limit visibility. Therefore, if the prospective reservoir area is located in an arid or semi-arid region, seasonality may not be a constraint for satellite images collection. On the contrary, humid regions may require specific satellite data tasking during low or high vegetative periods.
A careful analysis of these variables allows to efficiently tune selection of archive satellite data and collection of new ones to meet end-users (from academic researchers to private and public) specific needs. In this regard, a valuable support has been recently provided by Synthetic Aperture Radar (SAR) and multispectral imagery of the different space agencies’ constellations (Tapete and Cigna 2019). These open-access and licensed images integrate each other providing both landscape (multispectral imagery) and small scale archaeological feature (SAR) identification, global spatial coverage, high temporal revisit and ease of data handling.
Another important result is represented by the number of variables useful to identify CNH that emerged from the manual identification based on COSMO-SkyMed and Sentinel-2 derived products. These include: 1) the shape of the archaeological sites; 2) the terrain colour; 3) unexpected irregularities of some elements of the territory; 4) the location of anomalies along abandoned meanders of the rivers considered.
We aspire that these achievements will pave the way for the integration of the workflow in a detailed PCARA protocol to be used in the development of ad hoc policy papers for international and national stakeholders to protect CNH threatened by dams.
For the purposes of ESA LPS22, this paper will address several objectives of session D2.12, such as, highlighting the benefits of multidisciplinary collaborations and partnerships between different heritage experts, demonstrating how to shape the exploitation of Sentinel and other Copernicus missions data to meet end-users needs, and contributing to the evidence base via sharing of developed use-cases and respective lessons learnt.


REFERENCES
Agapiou, Athos. 2017. “Remote Sensing Heritage in a Petabyte-Scale: Satellite Data and Heritage Earth Engine© Applications.” International Journal of Digital Earth 10 (1): 85–102.
Marchetti, Nicolò, Gabriele Bitelli, Francesca Franci, and Federico Zaina. 2020. “Archaeology and Dams in Southeastern Turkey: Post-Flooding Damage Assessment and Safeguarding Strategies on Cultural Heritage.” Journal of Mediterranean Archaeology 33 (1): 29–54.
Tapete, Deodato, and Francesca Cigna. 2019. “Detection of Archaeological Looting from Space: Methods, Achievements and Challenges.” Remote Sensing 11 (20).
Zaina, Federico. 2019. “A Risk Assessment for Cultural Heritage in Southern Iraq: Framing Drivers, Threats and Actions Affecting Archaeological Sites.” Conservation and Management of Archaeological Sites 21 (3): 184–206.

The European Directive on open data and the re-use of public sector information (2019; a successor of PSI Directive, 2003) identifies “Earth observation and environment” as one of high-value datasets categories that is to say “documents the re-use of which is associated with important benefits for society, the environment and the economy, in particular because of their suitability for the creation of value-added services, applications and new, high-quality and decent jobs, and of the number of potential beneficiaries of the value-added services and applications based on those datasets”. On a global scale, Group for Earth Observation (GEO) has launched a dedicated Initiative, EO for Sustainable Development (EO4SDG) in Service of Agenda 2030 (Global Goals for Sustainable Development).
Within such a framework of open geospatial information (including EO) in support to specific SDGs (namely Goal 11 “Sustainable cities and communities” and goal 15 “Life on land”), this paper explores how satellite earth observation (EO) for purposes of cultural heritage monitoring is being portrayed across Europe, within both scientific and grey literature.
The objective of this study is to answer several research questions: (i) firstly, what are the main categories of damages to cultural heritage studied using satellite imagery in Europe so far (scientific literature)? Is it possible to assess a group of the most studied sites until now and the threats that have been associated to them? And, in case, what (if any) impact have these studies produced on the work of public administrations and site managers, and end-users in general (grey literature) on several identified case studies?
In order to explore the above listed aspects, the authors have taken into consideration that over the last few decades, the long-term trend of risks and damages to the archaeological heritage has received an increasing interest among scholars. Building upon a previously tested methodology (Zaina & Cuca, 2022), the paper is looking to identify an exhaustive number of documents that provide a focus on the evolution of the indexed scientific literature and grey literature (reports, working and government documents, white papers and so on) relying on the use of EO for monitoring of Cultural Heritage and Cultural Landscapes.

Few hundred papers regarding the sites across Europe published since 2005 have been identified for the purpose, following the procedure described below:
• Firstly (Step 1), papers were automatically retrieved from the Scopus® scientific database using several different combinations of synonyms for “damage” (relating to satellite, heritage and archaeology), which are present in the title, abstract and keywords of each indexed paper. We chose Scopus because it is the largest abstract and citation database of peer-reviewed literature including thousands of scientific journals, books and conference proceedings and it delivers a comprehensive overview of the world's research output in any field of study.
• From the resulting sample of 1531 papers, we applied the Excel® “automatic duplicate removal” to delete 837 duplicate papers (Step 2).
• The remaining 694 papers were then subjected to a detailed manual screening (Step 3) in order to exclude all those which, although including two or more keywords, did not deal specifically with the topic of damage to cultural heritage. The manual screening was carried out by analyzing the title, abstract and keywords and, in case of poor or lack of exhaustive information, by directly accessing the paper. Examples of off-topic papers are those analyzing climate change or catastrophic events (e.g., earthquakes, volcanic eruptions) that occurred in the past.

Hence a total number of almost 700 on-topic papers emerged from the manual screening and are subject to further investigation.

In parallel, a second survey has been carried out to screen and investigate the grey literature, under the following motivations:
• the scientific literature alone cannot provide an exhaustive representation of demonstration activities involving or made directly by users and stakeholders (as observed in previous studies; e.g. Tapete & Cigna, 2017), given that journal papers are mostly focused around 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 EO technologies on daily practice;
• not all demonstration activities have necessarily translated into papers or be presented at conferences with indexed publications, whereas reports from European projects and/or practitioner associations are more informative in this regard;
policy, programmatic and institutional documents issued by organisations and bodies in charge of heritage preservation can provide insights into the status of EO technology uptake and embedding in operational workflows.

Based on the analysis of such diverse documentations, the discussion will be around:
• apparently uneven distribution of evidence base across topics of concern for heritage documentation and preservation, in relation to the fact that some of these topics are directly related to specific functions (e.g. inventorying sites and regular monitoring of their condition) and/or the existence of regulatory frameworks, national or European policies or directives (e.g. the European Landscape Convention, Common Agricultural Policy) that the heritage administrations are requested to undertake and address;
• the variety of situations that seems to be found across Europe, from (i) heritage administrations that are already acquainted with satellite technologies (not rarely as a recent extension from consolidated expertise in aerial photography) so as to include them among their data sources and means for documentation, (ii) to situations where the technology is yet to be approached or the demonstration process has not yet been followed by a local capacity built or established;
• the role of “facilitator” / “accelerator” that scientific partners or specialist consultants can play to help heritage administrations to take advantage of EO technologies;
• the benefit from multidisciplinary collaboration, especially in governmental and international initiatives.

The main envisaged contribution of this analysis is a potential betterment of procedures in cultural heritage sites protection, monitoring and, ultimately, management. The results of this work aim to further contribute to reframing priorities for recording, documenting and monitoring of built heritage, especially bigger sites inserted in a larger framework of Cultural Landscapes.

The human presence in the Arctic has resulted in a rich legacy of archaeological, historical and cultural sites, many of which are at risk from anthropogenic impacts. Climate change in the Arctic impacts human heritage on a devastating scale, including coastal erosion, damaging or destroying coastal archaeological sites, to biological and chemical processes that are accelerating, causing decay, disturbance and, ultimately, the destruction of objects and structures. Climate change has also provided opportunities for the theft of woolly mammoth tusks from previously frozen ground, many from archaeological sites, and increased general tourist 'souveniring' of material culture.

Local communities cultural safety is at risk through the theft, damage or destruction of cultural objects and places of spiritual, cultural and historical significance. Central to the research is respectful engagement with the Peoples of the North to coproduce knowledge that is requested by them. There will be a strong emphasis on providing communities with opportunities and support for knowledge and transfer of skills in how to utilise remote sensing resources.

Space-based resources are already providing data that has increased knowledge of littoral and terrestrial changes, and changes in flora and fauna and enhanced responses by communities, archaeologists and heritage practitioners. Increasingly, indigenous peoples have utilised space-based resources to produce data for use in their endeavours to retain their traditional lifeways and enhance their lifestyles.

New possibilities for assessment and mapping of known sites, discovery of previously unrecognised sites, three-dimensional mapping, change-detection and site monitoring at high temporal resolution are emerging as a result of a number of developments in both spaceborne and airborne remote sensing technology and associated geoinformatic approaches. Especially significant developments are the maturing of structure-from-motion techniques, the rapid development of publicly accessible cloud-based image processing coupled with an increase in availability of medium-resolution satellite imagery, the expansion in scope and sophistication of free open-source software, the growing overlap between scientifically capable and consumer-grade UAV systems, and changes in the regulations relating to the use of UAVs in many countries. These changes can all potentially further increase the scope for co-production of knowledge and understanding of indigenious and other cultural assets; enhancing cultural heritage understanding, appreciation, conservation and protection.

Scientists, engineers, polar historians, heritage scholars and other social scientists are encouraged to attend this session to gain information, establish and enhance their networks, and explore future collaborations.