Digital Earth: Big Earth Data

Human beings have entered the age of ‘big data’. From 2005 to 2020, the digital universe is expected to grow by a factor of 300, from 130 exabytes to 40,000 exabytes, or 40 trillion gigabytes. Another way to look at this is that from now until 2020, the production of digital bits is likely to double approximately every two years (Gantz and Reinsel 2012). This data deluge encompasses not only volume and velocity, but also variability and diversity of structure, and comprehensiveness of perspectives. Big data can ‘enable enhanced decision-making, insight discovery and process optimization’ (Beyer and Laney 2012).

The research on big data has gradually developed and become a focus of attention for many domains, from science and technology, to economics and social sciences, and for society in general. Many countries have strategically enhanced their big data research and industries at a national level. These developments suggest that the big data phenomenon is becoming a new method for scientific research – changing the paradigm from model-driven to data-driven research.

Looking more specifically at big geo-referenced data, the vast multi-dimensional and multi-perspective geo-data have proved to be extremely useful in assisting humans to better understand the Earth and to help policy-makers take certain actions to begin solving some of our most pressing problems. In many ways, Digital Earth, as a collection of technologies that has matured over the years, could be seen as a successful example of ‘big data’. Digital Earth integrates the huge and valuable geo-data resources into a digital representation of the planet. In this regard, Digital Earth performs well in acquiring, storing and applying quadrillions of bytes of geo-referenced information through the use of advanced sciences and technologies, including computational science, mass storage, satellite imagery, broadband networks, interoperability, and metadata (Gore 1998). Furthermore, Digital Earth will simulate and render in real-time interactions among all Earth system processes in all spheres with respect to their physical, chemical, biological and social science elements by integrating various Earth observation data.

If we look back at the data we generated and the methodologies we used to manage these data, it becomes obvious that promoting better ‘use’ is the real target in the new era of big data. How to make more efficient and effective use of the data is right at the core of what the big data phenomenon and makes us think about it more deeply. Different stake holders are interested in the information that they want or need. We have collected great volumes of geo-spatial data about cities, farming fields, grasslands, mountains, rivers, oceans, and so on, and produced all kinds of maps, reports and research results through the application of specific Digital Earth technologies. Are the scientific and technical dimensions all that we should consider? Between the source of the data and the result, what are the most efficient and effective processes to extract the greatest value from the data? Are the specific categories and scales in analyzing the huge amounts of imagery data appropriate and sufficiently robust? Could we obtain more valuable information from the data to benefit the society and economy? We need to think carefully about developing the deep and potential increases in value from using the data and the models, trends and correlations hidden among the data.

About 10 years ago, somebody asked me what ‘Digital Earth’ is. ‘It means you put the “Earth” into your computer.’ It was my answer at that time. However, if you ask me the question again today, my new answer is that Digital Earth is now Big Earth Data, from the big data point of view.

When we study the relationship between big data and Digital Earth, we are facing a series of challenges such as the sensing of big data, high-performance processing of semi-structured and unstructured big data, data de-duplication and energy-efficient big data storage, communication and processing. We have a series of research questions for big data, including: How to express big data in Digital Earth? How to process big data in Digital Earth with acceptable cost? and in Digital Earth, what is the mechanism for the successful evolution of big data? I call our colleagues to pay attention to these topics and to study them.

We are publishing six papers in this issue, mainly focusing on the advance of Digital Earth. One paper summarizes several recent developments in Digital Earth, explores the implications of Digital Earth on citizen science, and proposes a suite of principles related to the development of Digital Earth. Another article proposes an algorithm to support the operationalization of the Digital Earth vision in terms of intelligent data discovery from vast quantities of geo-referenced data. A third contribution introduces a parasitic model and proposes that the model make data from Digital Earth operable on mobile phones. The fourth examines a client-server hybrid rendering approach for 3D urban building models and the fifth presents an integrated framework related to disaster response. The sixth one is a letter, which introduces a Digital Earth curriculum and discusses its importance.

I would like to take this opportunity to thank all the Editorial Board members, authors and reviewers who have contributed to the issues in volume 6 of 2013. International Journal of Digital Earth has been currently more focusing on the science and technology of Digital Earth and its applications at a regional or global scale to make the journal unique in its academic field. I sincerely welcome all researchers working in the Digital Earth area to contribute to International Journal of Digital Earth.

Huadong Guo

Editor-in-Chief