Ruixia Yang

Archeological crop marks identified from Cosmo-SkyMed time series: the case of Han-Wei capital city, Luoyang, China

ABSTRACT The development of spaceborne Synthetic Aperture Radar (SAR) technology declares that the golden era of SAR remote sensing in archeology is approaching; however, nowadays its methodology framework is still lacking due to the inadequate case studies validated by ground-truths. In this study, we investigated the crop marks using multi-temporal Cosmo-SkyMed data acquired in 2013 by applying a two-step decision-tree classifier in conjunction with a spatial analysis in an area of archeological interest nearby the archeological site of Han-Wei capital city (1900–1500 BP), in Luoyang, China. The time-series backscattering anomalies related to the wheat growth cycle were identified and then further validated in two zones by geophysical investigations (Ground Penetration Radar and electrical measurements) and in a third zone by archeological excavations made after the SAR data acquisition. This study provides a new approach for the relic detection, shallowly buried and covered by the crop vegetation, by temporal crop marks on spaceborne SAR images. We also emphasize the necessity to establish a satellite-to-ground methodology framework for the promotion of remote-sensing technology in archeology.

Synthetic Aperture Radar (SAR) Interferometry for Assessing Wenchuan Earthquake (2008) Deforestation in the Sichuan Giant Panda Site

Abstract: Synthetic aperture radar (SAR) has been an unparalleled tool in cloudy and rainy regions as it allows observations throughout the year because of its all-weather, all-day operation capability. In this paper, the influence of Wenchuan Earthquake on the Sichuan Giant Panda habitats was evaluated for the first time using SAR interferometry and combining data from C-band Envisat ASAR and L-band ALOS PALSAR data. Coherence analysis based on the zero-point shifting indicated that the deforestation process was significant, particularly in habitats along the Min River approaching the epicenter after the natural disaster, and as interpreted by the vegetation deterioration from landslides, avalanches and debris flows. Experiments demonstrated that C-band Envisat ASAR data were sensitive to vegetation, resulting in an underestimation of deforestation; in contrast, L-band PALSAR data were capable of evaluating the deforestation process owing to a better penetration and the significant coherence gain on damaged forest areas. The percentage of damaged forest estimated by PALSAR decreased from 20.66% to 17.34% during 2009–2010, implying an approximate 3% recovery rate of forests in the earthquake

Multi-scale synthetic aperture radar remote sensing for archaeological prospection in Han Hangu Pass, Xin'an China

ABSTRACT Increasing availability of multi-resolution synthetic aperture radar (SAR) data enabled us to demonstrate the benefits of the existing imaging solutions offered by radar satellites for purposes of archaeological prospection. In this study, mid-resolution L-band phased array type L-band synthetic aperture radar (PALSAR) to high-to-very-high-resolution X-band TerraSAR-X/TanDEM-X TerraSAR-X add-on for digital elevation measurements (TanDEM-X) (Stripmap/Staring Spotlight) images were synergistically applied for the archaeological prospection at the Han Hangu Pass, in Xin’an, China. First, the evidence and the stretching direction of the outer walls of the pass were identified from the temporal-averaged products of PALSAR and the terrain from TanDEM Co-registered Single-Look Data. Then, the spatial layout of archaeological monuments (previously documented as well as recently discovered) was observed in the visualization-enhanced Staring Spotlight TerraSAR-X imagery owing to its high spatial and radiometric resolution. The findings of this study highlight the effectiveness of using integrated multi-scale SAR remote sensing data from different platforms in archaeology.

The study of size-grade of prehistoric settlements in the Circum-Songshan area based on SOFM network

Choosing site area, cultural layer thickness, significant relics and significant remains as the variables, we applied cluster analysis to the ancient settlements of four cultural periods, respectively, which were Peiligang, Yangshao, Longshan and Xiashang, in 9000–3000 a BP, around Songshan Mountain. Through application of the SOFM (self-organizing feature map) networks, every type of ancient settlements was classified into different size-grades. By this means, the Peiligang settlements were divided into two grades, Yangshao and Longshan settlements were divided into three grades, respectively, and Xiashang settlements were divided into four grades. The results suggested that the size-grade diversity of ancient settlements was not significant during the Peiligang period in this area. Around the middle-late Yangshao period (5000 a BP), the size-grade diversity of ancient settlements began to appear, a process that continued during the Longshan period and finally matured in the Xiashang period. Moreover, the results reflected the regional differences in cultural characteristics in a particular period, which were mainly represented in that there were three Peiligang cultural systems distributed in different areas. Such differences also existed in the spatial distributive characteristics between the Xia and Shang cultures. Based on the size-grade study of ancient settlements in the Circum-Songshan area, it was found that the SOFM networks method was very suitable for size-grade classification of ancient settlements, since, using this method, adjacent cells would compete and learn from each other, a benefit that reduced the effect on classification by the inaccuracy of site acreages.

Auto-Extraction of Linear Archaeological Traces of Tuntian Irrigation Canals in Miran Site (China) from Gaofen-1 Satellite Imagery

This paper describes the use of the Chinese Gaofen-1 (GF-1) satellite imagery to automatically extract tertiary Linear Archaeological Traces of Tuntian Irrigation Canals (LATTICs) located in the Miran site. The site is adjacent to the ancient Loulan Kingdom at the eastern margin of the Taklimakan Desert in western China. GF-1 data were processed following atmospheric and geometric correction, and spectral analyses were carried out for multispectral data. The low values produced by spectral separability index (SSI) indicate that it is difficult to distinguish buried tertiary LATTICs from similar backgrounds using spectral signatures. Thus, based on the textual characteristics of high-resolution GF-1 panchromatic data, this paper proposes an automatic approach that combines joint morphological bottom and hat transformation with a Canny edge operator. The operator was improved by adding stages of geometric filtering and gradient vector direction analysis. Finally, the detected edges of tertiary LATTICs were extracted using the GIS-based draw tool and converted into shapefiles for archaeological mapping within a GIS environment. The proposed automatic approach was verified with an average accuracy of 95.76% for 754 tertiary LATTICs in the entire Miran site and compared with previous manual interpretation results. The results indicate that GF-1 VHR PAN imagery can successfully uncover the ancient tuntian agricultural landscape. Moreover, the proposed method can be generalized and applied to extract linear archaeological traces such as soil and crop marks in other geographic locations.

Investigating Luoyang by Remote Sensing: First Results

Since the launch of the Silk Road Economic Belt (SREB) initiative in China, archaeological prospection has been increasingly emphasized by archaeologists, scientists, and government officials to uncover the civilization of the past and the evidence of the friendship between West and East. Compared with traditional field archaeology, remote sensing is an irreplaceable tool in archaeological investigations, taking advantage of large spatial coverage and high-spectral sensitivity to anomalies linking the occurrence of buried relics. In the framework of a Chinese–Italian bilateral project entitled “Smart Management of Cultural Heritage Sites in Italy and China: Earth Observation and Pilot Project,” in 2014 we undertook preliminary investigations on some test sites in Han-Wei capital city and Dingding Gate in Luoyang City toassess the performance of remote sensing, including space-borne synthetic aperture radar (SAR), unmanned aerial vehicles (UAV), and the surface geoelectrical method for the detection of archaeological features. The investigations have been planned considering that the characteristics of the expected archaeological features and the subsoil are not ideal for applications based on the use of remote sensing and geophysics. In fact, past archaeological excavations unearthed deep walls built in rammed earth with stone foundations covered by clayey soil. The aim of this preliminary investigation campaign has been to provide indications for a cost-efficient scientific mission to be conducted in the future on wider areas in Luoyang with the prospect of performing archaeological excavations.

Corona Satellite Pictures for Archaeological Studies: A Review and Application to the Lost Forbidden City of the Han–Wei Dynasties

This paper provides a state of the art of the use of declassified satellite Corona for archaeological application and deals with the use of historical archives of Corona and aerial photographs for detecting ancient hidden cultural relics that may be completely lost in the modern landscape veiled by current land uses and land covers. Geospatial analysis is adopted to identify, extract and map the subtle archaeological features and cultural landscape of the lost Han–Wei Forbidden City in the Henan Province (China). It was one of the most important cities of ancient China, served as the capital for a long period, from the Eastern Zhou (2600 BP, Zhou Dynasty) to the Eastern Han and Wei Dynasties (1900–1500 BP). Outputs from our investigations clearly provided evidence of numerous buried structures of potential archaeological interest that were compared with historical documentation and excavations carried out in the area. The geospatial analysis, applied both to aerial photograph and to Corona pictures, enabled us to discover a number of unknown sub-palaces and structures, thus providing new insights for this important archaeological area.

Temporal-spatial distribution of archaeological sites in the Nihewan-Huliu Basin during the Paleolithic-Neolithic and Iron Age in northern China

The Nihewan-Huliu Basin is one of the great regions of human evolution, located in geographical transition zone. This study reveals the temporal-spatial distribution of archaeological sites based on the DEM (Digital Elevation Model) data, and analyses the changes for four periods (Paleolithic-Neolithic transition, Neolithic Age, Bronze Age and Iron Age). These sites expanded from the Sanggan River to the Huliu River and from the central and lower Huliu River to its upper reaches. The population and cultural development in the Nihewan Basin gradually lagged behind the Huliu River Baisin after the Paleolithic-Neolithic transition Age, because of the environmental impacts. The results may aid the understanding and study of the cultural heritage and civilization evolution in northern China.