TECHNICAL APPROACHES AND INSTRUMENTS
Satellite imagery
© Unitar/UNOSAT
When seeking to obtain an initial overview of the overall damage, a useful source is the satellite imagery published by UNOSAT. Its imagery analysis and satellite solutions are available to relief and development organisations within and outside the UN system and in the public domain.
In the Middle East, assessing war damage has become a regular feature as a precursor of action to address humanitarian relief, security, and strategic territorial and development planning. Satellite images with an analysis of war damage are already available for numerous old cities in the region.
Regularly updated satellite imagery is also available online, including from Google Earth and Bing Maps. Although these services do not provide analytical tools, users can zoom in on old cities and see a detailed view of the situation on the ground.
The extent of damage suffered by the urban heritage can usually be assessed for initial purposes with the aid of these and similar sources of satellite imagery.
Overlay of satellite images with morphological maps
Overlay © UNOSAT and BTU Cottbus
In order to determine the damage inflicted on the cultural heritage of an old city more precisely, the information from satellite images can be overlaid with other information.
Where basic maps containing historical information are available, such overlays can be produced relatively easily. Even if such maps are not available, the necessary information can usually be retrieved from existing registers, documents or digital archives.
If done properly, such overlays allow users to demarcate areas in which heritage buildings or sites have suffered damage to a similar extent, from minor to complete destruction. Identifying important sites and elements of the urban fabric that have been especially hard hit can help the relevant actors to adopt priority action plans, avoid further damage, and initiate emergency protection measures.
Drone reconnaissance flights
© Carlotta Erler/Picture alliance
Drones carrying a wide variety of sensors can be used for assessing the extent of war damage to urban cultural heritage. Drones, laser and photogrammetric technology, and supercomputers can be used in combination to produce high-quality images and even 3D models.
Compared with the more general assessment delivered by satellite imagery, drone surveys can record the damage suffered by historic buildings more precisely.
The use of drones presupposes a presence on the ground, however, and has to be approved by the competent authorities. Moreover, care has to be taken to ensure the safety and integrity of the city’s population and historic fabric.
Ground checks
© Yahya Arhab/Picture alliance/dpa
If access to locations is ruled out by political or security restrictions, feedback can be solicited from local people by way of crowdsourcing or social media. These tools can quickly and efficiently deliver a wealth of information, including photographs, written reports or other documents, and create a better understanding of the actual situation.
As soon as a war-damage urban centre becomes accessible again, targeted ground surveys can be conducted to validate information obtained by satellite imaging or remote sensing. Such surveys can contain photographs, videos and maps produced on the ground.
Overall damage assessment in the old city of Aleppo
Overlay © UNOSAT and BTU Cottbus
Work commenced on recording and assessing the damage to the World Heritage Site of the Old City of Aleppo in September 2012, shortly after the Battle of Aleppo had started. Since then, UNOSAT has published a number of damage assessment maps that document the progression of fighting and damage in the city. The most recent map was published in December 2016, by which time the fighting had ceased.
A UNESCO led emergency mission in January 2017 reported “extensive damage at the Great Umayyad Mosque, the Citadel, mosques, churches, souqs, khans, madrassas, hammams, museums and other significant historic buildings in Aleppo. According to a preliminary assessment, some 60% of the old city of Aleppo has been severely damaged, with 30% totally destroyed”.
Since then a wealth of information on Aleppo has been compiled, analysed and documented. A combination of historical information and new findings has produced a fairly clear picture of the extent of damage inflicted on the old city, and illuminated the tremendous effort that will be needed to recover its unique heritage.
