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

Hang Xu,Wei Zhou,Fulong Chen

doi:10.1186/s40494-021-00543-y

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 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.

Highlights

The Great Wall is one of the largest and oldest monuments globally and was designated a world cultural heritage site in 1987 due to its irreplaceable cultural and historical value [1]
The results indicated that the stability maps obtained from the persistent scatterer SAR interferometry (PSInSAR) and small baseline subset (SBAS) methods were generally consistent
In this study, deformation products were generated using high-resolution TSX data and PSInSAR and SBAS approaches to compare the suitability of the two approaches for deformation monitoring of the Shanhaiguan section of the Great Wall

Summary

Introduction

The Great Wall is one of the largest and oldest monuments globally and was designated a world cultural heritage site in 1987 due to its irreplaceable cultural and historical value [1]. The Great Wall was constructed intermittently for more than 2000 years from the Warring States period to the Qing Dynasty. It has a length of more than 21,000 km [2], passing through more than ten provinces in China and spanning different geomorphic units, such as mountains, valleys, deserts, and grasslands. The linear structure and the large extent of the Great Wall challenge traditional deformation monitoring methods, such as on-site visual inspection and fixed sensor deployment. Visual inspection [7, 8] is labor-consuming and may be dangerous for staff in desolate regions. For a fixed sensor-based method [9, 10], many sensors are required for large-area

Methods

Results

Discussion

Conclusion