Vasiliki Lysandrou

Cultural heritage management and monitoring using remote sensing data and GIS: the case study of Paphos area, Cyprus

Cultural heritage (CH) sites are threatened from a variety of natural and anthropogenic factors. Innovative and cost effective tools for systematic monitoring of landscapes and CH sites are needed to protect them. Towards this direction, the article presents a multidisciplinary approach, based on remote sensing techniques and Geographical Information System (GIS) analysis, in order to assess the overall risk in the Paphos district (Cyprus). Paphos region has a great deal of archaeological sites and isolated monuments, which reflect the long history of the area, while some of them are also listed in the UNESCO catalogue of World Cultural Heritage sites. Several natural and anthropogenic hazards have been mapped using different remote sensing data and methodologies. All data were gathered from satellite images and satellite products. The results from each hazard were imported into a GIS environment in order to examine the overall risk assessment based on the Analytic Hierarchy Process (AHP) methodology. The results found that the methodology applied was effective enough in the understanding of the current conservation circumstances of the monuments in relation to their environment as well as predicting the future development of the present hazards.

Risk assessment of cultural heritage sites clusters using satellite imagery and GIS: the case study of Paphos District, Cyprus

This paper aims to assess the risk of natural and anthropogenic hazards for cultural heritage in Cyprus by integrating multi-temporal GIS and earth observation analysis, in the area of Paphos District. The work presented here attends to re-evaluate previous results from earth observations and GIS analysis and go a step forward targeting more reliable outcomes for cultural heritage management. The scope of the paper was to develop a more accurate methodology for risk assessment against natural and anthropogenic hazards (e.g., soil erosion; urban expansion), based on homogeneous clustering of the monuments under consideration. The accomplished assessment approach, being lopsided and generic, cannot be applied across the board and undistractedly for cultural heritage management of all types of monuments of the district. Instead, the proposed clustering of monuments based on a variety of parameters is taking into consideration characteristics of their immediate environment, resulting rational local-based outcomes more useful for monuments and sites safeguarding and for prevention measurements. For each one of the five clusters of monuments located in the Paphos District, an analytical hierarchy process (AHP) method was followed in order to address the individual and unique characteristics of the monuments and sites within the same cluster area. Subsequently, the weight factors from these clusters were interpolated to the whole district, prior to the application of the overall AHP risk assessment. Ultimately, the results were compared with the overall AHP method applied for the entire Paphos District, indicating that the proposed methodology can be more accurate and realistic for the different groups of the monuments.

Cultural Heritage Sites in Danger—Towards Automatic Damage Detection from Space

The intentional damage to local Cultural Heritage sites carried out in recent months by the Islamic State have received wide coverage from the media worldwide. Earth Observation data provide important information to assess this damage in such non-accessible areas, and automated image processing techniques will be needed to speed up the analysis if a fast response is desired. This paper shows the first results of applying fast and robust change detection techniques to sensitive areas, based on the extraction of textural information and robust differences of brightness values related to pre- and post-disaster satellite images. A map highlighting potentially damaged buildings is derived, which could help experts at timely assessing the damages to the Cultural Heritage sites of interest. Encouraging results are obtained for two archaeological sites in Syria and Iraq.

The protection of cultural heritage sites from geo-hazards: The PROTHEGO project

Examining natural hazards responsible for cultural heritage damages all over Europe, especially over large or remote areas is extremely difficult, expensive and time consuming. There is a need identify and respond to natural hazards before they create irreparable damage to cultural heritage sites. The PROTHEGO project uses radar interferometry to monitor surface deformation with mm precision to analyze the impact of geo-hazards in cultural heritage sites in Europe. The project applies novel InSAR techniques to monitor monuments and sites that are potentially unstable due to landslides, sinkholes, settlement, subsidence, active tectonics as well as structural deformation, all of which could be affected of climate change and human interaction. To magnify the impact of the project, the approach will be implemented in more than 400 sites on the UNESCO World Heritage List (WHL) in geographical Europe. After the remote sensing investigation, detailed geological interpretation, hazard analysis, local-scale monitoring, advanced modelling and field surveying for the most critical sites will be carried out to discover the cause and extent of the observed motions. PROTHEGO (PROTection of European Cultural HEritage from GeO-hazards) is a collaborative research project funded in the framework of the Joint Programming Initiative on Cultural Heritage and Global Change (JPICH) – Heritage Plus in 2015–2018.

Establishing a Remote Sensing Science Center in Cyprus:First Year of Activities of ATHENA Project

ATHENA H2020 Twinning project is a three-year duration project and its main objective is to strengthen the Cyprus University of Technology (CUT) Remote Sensing Science and Geo-Environment Research Laboratory in the field of “Remote Sensing Archaeology” by creating a unique link between two internationally-leading research institutions: National Research Council of Italy (CNR) and the German Aerospace Centre (DLR). Through the ATHENA project, CUT’s staff research profile and expertise will be raised while S&T capacity of the linked institutions will be enhanced. In this paper the abovementioned objectives are presented through the various activities accomplished in the first year of the project. These activities include both virtual training by experts in topics such as active remote sensing sensors and sophisticated algorithms, as well as scientific workshops dedicated to specific earth observation and cultural heritage aspects. During this first year, outreached activities have been also performed aiming to promote remote sensing and other non-destructive techniques, including geophysics, for monitoring and safeguarding archaeological heritage of Cyprus. The ATHENA center aims to serve the local community of Cyprus, but at the same time to be established in the wider area of eastern Mediterranean.

Cities of the dead: approaching the lost landscape of Hellenistic and Roman necropoleis of Cyprus

An analytic approach of the numerous but poorly documented Hellenistic and Roman necropoleis of Cyprus, excavated or simply spotted through the years, is presented in this paper. Geographical Information Systems (GIS) were used so as to better understand the lost landscape of the Hellenistic and Roman necropoleis. GIS were applied to visualize, rationalize, and analyze the vast quantity of material, starting from the simple site location of the known Hellenistic and Roman cemeteries, proceeding with an analytic approach of the available scarce information, to reveal eventually specific spatial patterns. Initially, indexing, registration, topographic documentation, and mapping linked with all the necessary information of the known necropoleis were accomplished. In addition, spatial analysis considering environmental and other parameters in GIS was carried out in a macroscale perspective. The above analysis resulted notable aspects related to the lost funerary landscape of ancient Cyprus.

The use of UAVs for remote sensing applications: case studies in Cyprus

Unmanned aerial vehicles (UAVs) for use in remote sensing offer simple and affordable observation from the air. Due to the decreasing size of the sensors, receivers and antennas, it is now possible to create integrated low-altitude airborne systems. Remote sensing technologies on a UAV platform are an efficient, non-invasive and low cost resource for the detection, documentation and monitoring of various environmental (both natural and cultural) features, in high resolution and quality. Different remote sensing techniques can be used alongside to the UAVs, such as field spectroscopy, multispectral cameras, infrared cameras and thermal cameras. This integration in terms of techniques and technologies, contributes further to more solid outcomes depending on the case study. The possibility of adding a variety of sensors to the basic UAV unit amplifies both the application cases and the results. Among the types of camera sensors that can be used with the UAVs are the visible spectrum cameras, the multi-spectral cameras and the hyperspectral cameras. These cameras can extract more detailed information since an entire spectrum is acquired from each pixel of the image. In this paper, various UAVs used for environmental and archaeological applications in different areas of Cyprus are presented.

Mapping air pollution using Earth observation techniques for cultural heritage sites

Air pollutants, together with climatic parameters, are of major importance for the deterioration of cultural heritage monuments. Atmospheric pollution is widely recognized as one of the major anthropogenic threats to architectural cultural heritage, in particular when associated with water absorption phenomena. Atmospheric particle deposition on surfaces of Monuments (of cultural heritage interest) may cause an aesthetic impact induced by a series of chemical reactions. Therefore there is a need for systematic monitoring and mapping of air pollution for areas where important archaeological sites and monuments are found. observation techniques, such as the use of satellite image for the retrieval of Aerosol Optical Thickness (AOT), are ideal for this purpose. In this paper, all important monuments of the Paphos District, listed by the Department of Antiquities of Cyprus, have been mapped using Geographical Information Systems. Several recent (2012) MODIS satellite images (both Aqua and Terra) have been used to extract the AOT values in this area. Multi-temporal analysis was performed to identify areas of high risk where AOT values are considered to be high. In situ observations have been also carried out to verify the results.

Searching data for supporting archaeo-landscapes in Cyprus: an overview of aerial, satellite, and cartographic datasets of the island

The landscape of Cyprus is characterized by transformations that occurred during the 20th century, with many of such changes being still active today. Landscapes’ changes are due to a variety of reasons including war conflicts, environmental conditions and modern development that have often caused the alteration or even the total loss of important information that could have assisted the archaeologists to comprehend the archaeo-landscape. The present work aims to provide detailed information regarding the different existing datasets that can be used to support archaeologists in understanding the transformations that the landscape in Cyprus undergone, from a remote sensing perspective. Such datasets may help archaeologists to visualize a lost landscape and try to retrieve valuable information, while they support researchers for future investigations. As such they can further highlight in a predictive manner and consequently assess the impacts of landscape transformation -being of natural or anthropogenic cause- to cultural heritage. Three main datasets are presented here: aerial images, satellite datasets including spy satellite datasets acquired during the Cold War, and cadastral maps. The variety of data is provided in a chronological order (e.g. year of acquisitions), while other important parameters such as the cost and the accuracy are also determined. Individual examples of archaeological sites in Cyprus are also provided for each dataset in order to underline both their importance and performance. Also some pre- and post-processing remote sensing methodologies are briefly described in order to enhance the final results. The paper within the framework of ATHENA project, dedicated to remote sensing archaeology/CH, aims to fill a significant gap in the recent literature of remote sensing archaeology of the island and to assist current and future archaeologists in their quest for remote sensing information to support their research.

Earth observation technologies in service to the cultural landscape of Cyprus: risk identification and assessment

The Cultural landscapes are witnesses of “the creative genius, social development and the imaginative and spiritual vitality of humanity. They are part of our collective identity”, as it is internationally defined and accepted (ICOMOSUNESCO). The need for their protection, management and inclusion in the territorial policies has already been widely accepted and pursued. There is a great number of risks to which the cultural landscapes are exposed, arising mainly from natural (both due to slow geo-physical phenomena as well as hazards) and anthropogenic causes (e.g. urbanisation pressure, agriculture, landscape fragmentation etc.). This paper explores to what extent Earth Observation (EO) technologies can contribute to identify and evaluate the risks to which Cultural Landscapes of Cyprus are exposed, taking into consideration specific phenomena, such as land movements and soil erosion. The research of the paper is illustrated as part of the activities carried out in the CLIMA project - “Cultural Landscape risk Identification, Management and Assessment”. It aims to combine the fields of remote sensing technologies, including Sentinel data, and monitoring of cultural landscape for its improved protection and management. Part of this approach will be based on the use of InSAR techniques in order to monitor the temporal evolution of deformations through the detection and measurement of the effects of surface movements caused by various factors. The case study selected for Cyprus is the Nea Paphos archeological site and historical center of Paphos, which are listed as UNESCO World Heritage sites. The interdisciplinary approach adopted in this research was useful to identify major risks affecting the landscape of Cyprus and to classify the most suitable EO methods to assess and map such risks.