scholarly journals A comparative case study of MTInSAR approaches for deformation monitoring of the cultural landscape of the Shanhaiguan section of the Great Wall

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hang Xu ◽  
Fulong Chen ◽  
Wei Zhou

AbstractThe Great Wall of China is one of the largest architectural heritage sites globally, and its sustainability is a significant concern. However, its large extent and diverse characteristics are challenges for deformation monitoring. In this study, the Shanhaiguan section of the Great Wall was investigated in a case study to ascertain the damage and potential hazards of the architectural site. Two standard multi-temporal synthetic aperture radar interferometry (MTInSAR) technologies, including persistent scatterer SAR interferometry (PSInSAR) and small baseline subset (SBAS) SAR interferometry, were used for deformation monitoring using high-resolution TerraSAR-X data acquired in 2015–2017. The results of the two MTInSAR approaches reveal the health condition of the Great Wall. The Shanhaiguan section was stable, but local instabilities caused by rock falls were detected in some mountainous areas. In addition, the applicability of PSInSAR and SBAS was evaluated. The performance analysis of the two approaches indicated that a more reliable and adaptable MTInSAR technique needs to be developed for monitoring the Great Wall. This study demonstrates the potential of MTInSAR technology with high-resolution data for the health diagnosis of heritage sites with a linear structure, such as the Great Wall.

2021 ◽  
Author(s):  
Hang Xu ◽  
Fulong Chen ◽  
Wei Zhou

Abstract The Great Wall of China is one of the largest architectural heritage sites globally, and its sustainability is a significant concern. However, its large extent and diverse characteristics cause challenges for deformation monitoring. In this study, the Shanhaiguan section of the Great Wall was investigated in a case study to ascertain the damage and potential hazards of the architectural site. Two standard multi-temporal synthetic aperture radar interferometry (MTInSAR) technologies, including persistent scatterer SAR interferometry (PSInSAR) and small baseline subset (SBAS) SAR interferometry, were used for deformation monitoring using high-resolution TerraSAR-X data acquired in 2015–2017. The results of the two MTInSAR approaches revealed the health condition of the Great Wall. The Shanhaiguan section was stable, but local instabilities caused by rock falls were detected in some mountainous areas. In addition, the applicability of PSInSAR and SBAS was evaluated. The performance analysis of the two approaches indicated that a more reliable and adaptable MTInSAR technique needs to be developed for monitoring the Great Wall. This study demonstrates the potential of MTInSAR technology with high-resolution data for the health diagnosis of heritage sites with a linear structure, such as the Great Wall.


2021 ◽  
Author(s):  
Hang Xu ◽  
FuLong Chen

<p>Architectural heritage is cultural and spiritual symbol of our predecessors with immeasurable historical, artistic, and technological value. However, these heritages are exposed to long-term degradation due to the combination impacts from the natural erosion and anthropogenic activities. Consequently, it is important to establish an effective deformation monitoring system to support the sustainable conservation of those properties. In order to make complementary to conventional geodetic measurements such as global navigation satellite systems (GNSS) and leveling in terms of spatial density, we propose a landscape-ontology scale multi-temporal InSAR (MTInSAR) solution for the preventive deformation monitoring of large-scale architectural heritage sites through the adaption of current MTInSAR approaches. We apply different solutions in Shanhaiguan section of the Great Wall in China and the Angkor Wat in Cambodia based on their onsite characteristics. At the cultural landscape scale, we improve the small baseline subset (SBAS) approach by the induced pseudo-baseline strategy in order to avoid the errors caused by inaccurate external DEM, resulting in a robust deformation estimation in mountainous areas where the architecture heritage of the Great Wall located; at the ontology scale, we integrate the differential SAR tomography (DTomoSAR) with the finite element method (FEM) for the structural instability detection of the Angkor Wat Temple, pinpointing the structural defects from the 3D deformation measurements and simulation. This study demonstrates the capability of adaptive MTInSAR approaches for the preventive monitoring the deformation of large-scale architectural heritage sites.</p><p><strong>Keywords</strong>: Architectural heritage; two-scale; deformation; MTInSAR</p>


2018 ◽  
Vol 45 (22) ◽  
pp. 12,340-12,349 ◽  
Author(s):  
Olga Engels ◽  
Brian Gunter ◽  
Riccardo Riva ◽  
Roland Klees

2021 ◽  
Author(s):  
Athanasia-Maria Tompolidi ◽  
Issaak Parcharidis ◽  
Constantinos Loupasakis ◽  
Michalis Fragkiadakis ◽  
Pantelis Soupios ◽  
...  

<p>Cultural heritage is a key element of history as the ancient monuments and archaeological sites enrich today’s societies and help connect us to our cultural origins. The project entitled ''SpaCeborne SAR Interferometry as a Nonivasive tool to assess the vulnerability over Cultural hEritage sites (SCIENCE)'' has as ultimate objective to predict the vulnerability of the archaeological sites to ground deformation in time and space and protect them against natural/man-made damage. The SCIENCE project aims to develop, demonstrate, and validate, in terms of geotechnical local conditions and monuments’ structural health, SAR interferometric techniques to monitor potential ground deformation affecting the archaeological sites and monuments of great importance. </p><p>During the last few years, spaceborne Synthetic Aperture Radar (SAR) interferometry has proven to be a powerful remote sensing tool for detecting and measuring ground deformation and studying the deformation’s impact on man-made structures. It provides centimeter to millimeter resolution and even single buildings/monuments can be mapped from space. Considering the limitations of conventional MT-InSAR techniques, such as Persistent Scatterers Interferometry (PSI), in this project a two-step Tomography-based Persistent Scatterers (PS) Interferometry (Tomo-PSInSAR) approach is proposed for monitoring ground deformation and structural instabilities over the Ancient City Walls (Ming Dynasty) in Nanjing city, China and in the Great Wall in Zhangjiakou, China. The Tomo-PSInSAR is capable of separating overlaid PS in the same location, minimizing the unfavorable layover effects of slant-range imaging in SAR data. Moreover, the demonstrations are performed on well-known test sites in China and in Greece, such as: a) Ming Dynasty City Walls in Nanjing, b) Great Wall in Zhangjiakou, c) Acropolis complex of Athens and d) Heraklion walls (Crete Island), respectively.</p><p>In particular, in the framework of SCIENCE project are processed several radar datasets such as Sentinel 1 A & B data of Copernicus program and the high resolution TerraSAR-X data. The products of Persistent Scatterers Interferometry (PSI) are exported in various formats for the identification of the persistent scatterers using high resolution optical images, aerial photographs and fusing with high accuracy Digital Surface Models (DSM). In addition, the validation of the results is taking place through in-situ measurements (geological, geothechnical e.t.c) and data for the cultural heritage sites conditions.</p><p>SCIENCE project’s final goal is the risk assessment analysis of the cultural heritage monuments and their surrounding areas aiming to benefit institutions, organizations, stakeholders and private agencies in the cultural heritage domain through the creation of a validated pre-operation non-invasive system and service based on earth observation data supporting end-user needs by the provision knowledge about cultural heritage protection. In conclusion, SCIENCE project is composed by a bilateral consortium of the Greek delegation of Harokopio University of Athens, National Technical University of Athens, Terra Spatium S.A, Ephorate of Antiquities of Heraklion (Crete), Acropolis Restoration Service (Athens) of Ministry of Culture and Sports and by the Chinese delegation of Science Academy of China (Institute of Remote Sensing and Digital Earth) and  International Centre on Space Technologies for Natural and Cultural Heritage (HIST) under the auspices of UNESCO (HIST-UNESCO).</p>


2020 ◽  
Author(s):  
Tao Li ◽  
Yangmao Wen ◽  
Lulu Chen ◽  
Jinge Wang

<p>Three Gorge area landslide hazards developed very fast after the Dam started to impound the water since 2007. There were lots of research literatures concentrated on the Badong Huangtupo Landslide area for the whole city center had to change its position in 2009. Several literatures used Envisat SAR images time series to monitoring the surface deformation from 2008~2010. The results showed good consistent with the water level changes and precipitation.  The high resolution TerraSAR Spotlight images had been used to monitoring the Shuping landslide and Fanjiaping landslide area in Zigui country from 2009~2012,the InSAR results showed good details of the landslide boundary and deformation rate with DInSAR technology.</p><p>This paper studies several landslide area in the Three Gorge by InSAR technology in the past few years, such as Huangtupo, Huanglashi , Daping and  Baiheping landslide area , etc. al . The high resolution SAR images covered Badong and Wushan area have been collected, including the Sentinel-1, TerraSAR, RadarSAT-2, ALOS-2 SAR images. The high resolution topography in those landslide area have been collected both by UAV lidar and high resolution topography map.</p><p>The Huangtupo landslide area changed a lot in the past 3 years with the buildings ruins cleared and red soil covered by the local government. The time series results by Sentinel data in this area shows the big changes but could not derive reasonable deformation results.</p><p>Three Gorges Research Center for Geo-hazards (TGRC) of China University of Geosciences(CUG) built the Badong field test site in Huangtupo landslide area. This test site is composed with a tunnel group and a series of monitoring system including the inside sensors, surface deformation monitoring sensors and so on. In this paper, we mounted several new designed dihedral corner reflectors on the Huangtupo landslide area for high precision deformation monitoring by InSAR. Both the  ascending and the  descending orbit data of RadarSAT-2 high resolution SAR image  and TerraSAR Spotlight images have been collected in this field.</p><p>The preliminary results from those new acquiring SAR data series show that the traditional landslide area such as Huanglashi , Daping, Baiheping are all moving slowly with good coherence in SAR image series.  The poor vegetation coverage in those landslide area helped to get the credible  InSAR results. The high resolution DEM is the critical elements for the DInSAR techniques in those landslide area. The steep  topography in those landslide area distorted the SAR images correspondingly.</p><p>Our results shows that it is possible to use ascending and descending high resolution SAR images to monitor the landslide area with mm level precision, while the vegetation is not so dense. High resolution SAR interferometry helped a lot for the landslide boundary detection and detailed analysis. The lower resolution SAR images such as Sentinel-1 still could provide some deformation results in landslide area, but it need more auxiliary data to interpret the results.</p>


Sensors ◽  
2018 ◽  
Vol 18 (5) ◽  
pp. 1606 ◽  
Author(s):  
Jeongyun Han ◽  
Eunjung Lee ◽  
Hyunghun Cho ◽  
Yoonjin Yoon ◽  
Hyoseop Lee ◽  
...  

Author(s):  
Howell Li ◽  
Lucy M. Richardson ◽  
Christopher M. Day ◽  
James Howard ◽  
Darcy M. Bullock

The three fundamental parameters of a traffic signal system are split, cycle, and offset. This paper describes the use of high-resolution data ( a) to identify time periods during which split parameters may be insufficient and ( b) to help practitioners identify opportunities for reallocating split time. A case study of seven corridors with 47 intersections is presented. A drill-down approach was developed to identify movements that could be improved by a reallocation of split times. A heuristic that can reallocate up to 5 seconds of underutilized green time on a competing phase was applied to those corridors. For the selected phase identified in this study, the adjustment reduced split failures by an average of 40% while also decreasing yellow occupancy an average of 40% and red light violations an average of 66%. The paper concludes by recommending that central systems implement drill-down dashboards. Such tools would enable easy identification and systemwide monitoring of split failures and would provide opportunities to reallocate slack time.


2017 ◽  
Vol 2017 ◽  
pp. 1-17
Author(s):  
Yi Yang ◽  
Chao Guan ◽  
Eerdun Hasi

Blowouts are an important ground indication of wind-sand activity in the Hulunbuir grassland. They include two basic geomorphologic units, erosion depression and sand deposition, and three typical morphological types: saucer type, trough type, and compound type. In this study, the dynamic changes of typical blowouts within the past decade were analyzed via multiperiod high-resolution remote sensing images. RTK was used to repeatedly measure the blowouts to obtain their high-precision 3D terrain data in 2010, 2011, and 2012. Short-term dynamic changes in 3D blowout morphology were carefully analyzed to discover the following. (1) From 2002 to 2012, the depressions of typical blowouts exhibited downwind extension and lateral expansion trends, as they continuously grew in size. Regarding the sand deposition zones, those of the saucer blowout grew continuously, while those of the trough and compound blowouts fluctuated between growth and contraction. (2) The erosion depression of saucer blowouts eroded downward and spread horizontally; that of trough blowouts first accumulated then eroded but also spread horizontally. The erosion depression of compound blowouts exhibited horizontal spreading accompanied with bottom accumulation. The sand deposition zones of all three types of blowouts exhibited decreasing length with increasing width and height.


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