Objective  Digital conservation is one of the most concerned issues in the field of world heritage in the 21st century. On the occasion of the 51st anniversary of the promulgation of the World Heritage Convention, this research tries to identify the key issues in digital conservation of world heritage, review the digital conservation practice of natural and cultural heritage, and interpret the transformative impact of digital technology on the world heritage system.

Methods  By combing through important international policy documents, official resolutions, and research and project reports related to the digital conservation of world heritage since 1972, this research analyzes the development and innovation of relevant concepts, policies and technologies. The research conducts a systematic analysis on 649 items highly related to digital conservation, which are obtained from authoritative open-access databases, such as the UNESDOC and the digital platform of world heritage consulting agencies, including IUCN Library System, ICCROM Library, ICOMOS Open Archive, etc. Some 7 groups of keywords are adopted for information search, such as “digital heritage”, “data”, “information service” and “information technology”, and CiteSpace, a biliometric analysis software, is used to analyse keyword co-occurrence and clustering relationships of the search results, in order to derive main issues in both natural and cultural heritage.

Results  According to the keyword clustering of the search results from IUCN Library System, the key directions for natural heritage digital conservation may be summarized as follows: 1) Survey and management methods for biological and environmental information; 2) analysis and sustainable use of natural resources; 3) community participation, conservation research and international cooperation based on information sharing. The keyword clustering results of ICCROM Library and ICOMOS Open Archive items show that the research and practice on digital conservation of world heritage mainly focus on traditional cultural heritage such as historic structures and towns, and archaeological sites, while paying less attention to cultural landscape, cultural routes, etc. Recent practice presents a rapid growth in the application of digital documentation technology, but still mainly relying on traditional means such as GIS for information management. Heritage interpretation and local capacity building technologies are relatively less seen in practice. Material analysis, risk assessment and disaster prevention, and mitigation are the main issues involving the application of digital technologies. Such issues as digital interpretation and virtual experience show greater potential for development with the penetration of digital technologies into the field of heritage tourism. This research identifies a digital conservation technology system centered on 4 major themes, 12 technical categories and 62 tool clusters, with the 4 major themes being recording and documentation, monitoring and management, presentation and interpretation, and international cooperation and capacity building with respect to world heritage. Digital technologies have had a transformative impact on the world heritage conservation system, driving the decentralization of heritage observation perspectives, innovation in decision-making process, increase in public accessibility and visitor-oriented heritage experience, and formation of a new world-wide mechanism for the production of knowledge. Based on the year-based distribution of the search results, and combined with the analysis of the aforesaid keywords and content of relevant articles, as well as the important time points of iconic projects, technological development and policy shifts, the main periods for digital conservation of both the natural and cultural heritage are identified with the main focuses demonstrated. The first digital conservation documents in the field of world heritage appeared in the 1970s. After the 1990s, the number of digital conservation documents rose significantly and entered a phase of rapid growth around 2005. The year-based distribution of search result shows a difference in development curve between the digital conservation of natural and cultural heritage, with that of natural heritage peaking in the 1990s and leveling off after 2000, while that of cultural heritage started to rise from the 2000s and has been extremely active in the past 15 years. The development of the digital conservation of natural heritage can be divided into 4 phases: 1) 1972−1990, support of species protection by database technology; 2) 1991−2005, digital monitoring and management of biodiversity and ecosystems; 3) 2006−2013, effectiveness assessment and capacity building for natural heritage conservation; 4) 2014 to present, integrated digital empowerment for natural heritage conservation. As for cultural heritage, the development of digital conservation can be summarized into 3 phases: 1) 1980−2005, conservation of physical cultural heritage supported by digital technology; 2) 2006−2016, multi-dimensional conservation of cultural heritage supported by digital technology; 3) 2017 to present, cultural turn of heritage conservation in the context of digital empowerment.

Conclusions  Looking ahead to the next 50 years, this research proposes four key directions for heritage conservation in the future: 1) integration and innovation of digital technologies for landscape heritage; 2) development of digital resources, tools, and data standards; 3) ethical framework and action norms for digital conservation; 4) capacity building for sustainable digital conservation. Through demonstrating the development history of the digital conservation of world heritage from a frontier direction focusing on technological application in the physical preservation of heritage sites, to a new field transforming our perspectives toward world heritage itself with the concept of digital heritage, this research may serve as an important reference for digital conservation of world heritage in China.