Google Earth (GE), a large Earth-observation data-based geographical information computer application, is an intuitive three-dimensional virtual globe. It enables archaeologists around the world to communicate and share their multisource data and research findings. Different from traditional geographical information systems (GIS), GE is free and easy to use in data collection, exploration, and visualization. In the past decade, many peer-reviewed articles on the use of GE in the archaeological cultural heritage (ACH) research field have been published. Most of these concern specific ACH investigations with a wide spatial coverage. GE can often be used to survey and document ACH so that both skilled archaeologists and the public can more easily and intuitively understand the results. Based on geographical tools and multi-temporal very high-resolution (VHR) satellite imagery, GE has been shown to provide spatio-temporal change information that has a bearing on the physical, environmental, and geographical character of ACH. In this review, in order to discuss the huge potential of GE, a comprehensive review of GE and its applications to ACH in the published scientific literature is first presented; case studies in five main research fields demonstrating how GE can be deployed as a key tool for studying ACH are then described. The selected case studies illustrate how GE can be used effectively to investigate ACH at multiple scales, discover new archaeological sites in remote regions, monitor historical sites, and assess damage in areas of conflict, and promote virtual tourism. These examples form the basis for highlighting current trends in remote sensing archaeology based on the GE platform, which could provide access to a low-cost and easy-to-use tool for communicating and sharing ACH geospatial data more effectively to the general public in the era of Digital Earth. Finally, a discussion of the merits and limitations of GE is presented along with conclusions and remaining challenges.
Historical records and archaeological discoveries have shown that prosperous agricultural activities developed in the ancient Juyan Oasis of northwestern China, an important oasis that once flourished on the ancient Silk Road. However, how the irrigation canals were distributed in historical time was unknown. Here, we identified and mapped the spatial distribution of ancient abandoned irrigation canals that were built using CORONA photographs and field inspections. This work found that ancient irrigation canals are large-scale and distributed throughout the desertified environment, with three hierarchical organization of first-, second-, and third-order irrigation canals (the total length of the first- and second-order-irrigation canals is dramatically more than 392 km). This study further indicates that ancient irrigation methods and modern irrigation systems in arid regions of China share the same basic irrigation design. New visual and fine-scale evidence and spatial distribution of irrigation canals are provided to illustrate the development of the ancient irrigated agriculture that occurred in the Juyan Oasis. This work is useful for readers who are interested in the construction and organization approaches of irrigation canals used in ancient irrigated agriculture in arid regions. It also has implications for how ancient people balance the relationships between human needs and the eco-environment using reasonable water management methods, especially for decision-making in the efficient usage of limited water resources in the arid inland river basin.