Digital Earth is a concept of an interactive digital replica of the entire planet that can facilitate a shared understanding of the multiple relationships between the physical and natural environments and society. To do so, it needs to be accessible globally from multiple platforms (mobiles, tablets, computers); be able to display information in ways that are easily understood by multiple audiences (the public, decision-makers, scientists); and be constantly updated with data coming from sensors (space-based, airborne, in-situ), citizens, and both public and private sectors. It must be able to focus on change (from the past, to present and future) and thus include not just data but also the outcomes of models and simulations to enable a wider understanding of the consequences of human action on the environment, and of environmental change on society. It must be a tool for scientific discovery and education, social interaction, and debate. It must also be fun to use to engage the younger generations, who are the future of our planet.
Governments and academia have contributed important components to Digital Earth by releasing large quantities of public sector and scientific information. In recent years, the private sector has created compelling visual representations of planet Earth, and citizens are providing a phenomenal amount of data through social networks. Within this fast-evolving landscape, the true challenge of Digital Earth is to connect the myriad information systems, data collections, and participants at all levels, from the very local to the global, in order to represent as clearly as possible the full complexity of the functioning of our planet.
Sharing information on environmental and social phenomena is at the heart of Digital Earth. To do so we need a framework of technologies, standards, organisational arrangements and policies that makes it possible to find, access, use, share, and publish such information, in other words we need an information infrastructure, or to be more precise we need to connect the multiple information infrastructures being developed across the world. Such infrastructures come in multiple flavours: they include information and services for citizens and business provided by national and local governments (e-government infrastructures, and more recently open data initiatives and portals), dedicated infrastructures for scientific information and data (research e-infrastructures), and the many platforms developed by the private sector to find and share information among the public at large, including social networks like Facebook or Twitter which have become particularly popular. In Europe, the Digital Agenda is a key flagship supporting the development of these infrastructures and open data initiatives. In this sense, Digital Earth is an important contribution to the Digital Agenda and the overall Europe 2020 objectives of smart, sustainable and equitable growth in the Union.
A key building block for Digital Earth is represented by those thematic information infrastructures addressing environmental and geographic information (Spatial Data Infrastructures, or SDIs). These have been developed over the past 20 years largely as a result of government efforts to have better information on which to base sound environmental policies. Europe is a world leader in developing SDIs as a result of its INSPIRE initiative, of which the JRC is the technical coordinator.
INSPIRE, the Infrastructure for Spatial Information in Europe, is a legal framework that requires Member States to document and share harmonised spatial and environmental datasets and services, and establish a technical infrastructure to make it possible to discover, view, transform and download them. INSPIRE is not a centralised system but is based on the interoperability of the many national and sub-national SDIs developed and maintained by the Member States across Europe. To achieve such interoperability, the JRC coordinates the development of the technical specifications for harmonising these datasets under 34 environmental themes, and to ensure that the Member States’ web services can communicate effectively. The reason INSPIRE is such a world leader is that most other SDIs in the world focus only on discovering and accessing existing information and not on harmonising the underlying data so that they can be used seamlessly across national borders.
The experience of the JRC in developing a multilingual and interoperable SDI across Europe is also of major benefit to the global endeavours to share Earth observations more effectively. Eighty-eight countries, the European Commission, and sixty-nine international organisations are contributing to this effort to develop a Global Earth Observation System of Systems (GEOSS). At the heart of GEOSS is a common infrastructure to search and access information, data, and services from major Earth observing systems. The JRC co-chairs the Implementation Board overseeing the development of this infrastructure, and contributes to its operations through a key component, the Data and Access Broker, that has been a leap forward in the ability to search and access data from heterogeneous global systems. The key feature of the brokering approach is that it does not seek to achieve interoperability by imposing a single set of standards on different systems, but recognises that diversity will always exist, and therefore it is necessary to build bridges across different communities, and their technical standards, protocols, and ways of operating. This is particularly important in the context of GEOSS; unlike INSPIRE, which is backed by a legal enforceable framework, GEOSS is a voluntary process, with limited financial resources. Therefore, trying to impose a single set of standards proved to be unworkable, and the brokering approach developed in the EuroGEOSS research project led by the JRC proved instead to be a key innovation. The possibility of building bridges to heterogeneous information systems and infrastructures is now also proving crucial in trying to integrate social networks into the Digital Earth framework.
Citizens and Sensors
Information infrastructures such as INSPIRE primarily address the sharing of official information held by governments at multiple levels that is relevant for environmental policy. This is a critical first step, but in order to fully develop the vision of Digital Earth and have an interactive, dynamic, and participative framework we need to harness the opportunity presented by the development of millions of cheap sensors that can monitor social and environmental phenomena such as traffic, air quality, temperature, etc., and the billions of social network users who exchange information on many aspects of their lives and their surroundings in real time.
Social network users can effectively act as human sensors, contributing observations, measurements, and important qualitative information about their perceptions of their environment and of change affecting them. When talking about data provided by the public for scientific or policy purpose, the question of data quality always comes to the fore. For this purpose the JRC has recently completed a large-scale research project to harness social network data and assess their quality and contribution to support environmental policy. Taking advantage of the operation by the JRC of the European Forest Fire Information Service, which monitors daily the presence, evolution, and outcome of forest fires in Europe via remote sensing, we compared the results of the data from satellites, with those coming from an analysis of millions of tweets sent by the public and referring to forest fires. The results of this comparison are very encouraging: not only were most of the forest fires spotted by satellites also identified by the public, but also the discrepancies could be explained satisfactorily, indicating that data provided by citizens are a valid supplement to official data, and when the latter are not available can also be particularly helpful as a first indication of emerging problems. Research on sensors and sensor networks was instead undertaken in the context of the ENVIROFI project (to which the JRC contributed) to identify the requirements of environmental policy users for new standards, protocols, and processes being developed as part of the Future Internet Public-Private Partnership initiative.
The Environmental Observation Web and its Service Applications within the Future Internet (ENVIROFI)
Image acquisition and storage
The JRC is in charge of image acquisition in the context of CAP (Common Agricultural Policy) Controls with Remote Sensing. Two types of images are acquired: satellite imagery and aerial photography. These are used for the management of feasibility studies. The JRC also produces image acquisition specifications and performs benchmarking studies of newly launched satellite sensors.
The main advantage of aerial photography with respect to very high resolution (VHR) satellite imagery is that it can cover much larger areas (e.g. large administrative units such as full provinces) in a limited period of time. However, acquiring aerial photography has also some constraints such as restrictions over military zones and air traffic lanes. Cloud cover is not as restrictive for aerial photography as it is for satellite imagery, but meteorological conditions do affect the radiometric quality of the photos. Moreover, the lead-time in the processing of analogue aerial photography (which requires developing, printing, scanning) may be longer than that for satellite images. Aerial photography acquisition must therefore be organised sufficiently in advance, and the acquisition periods should be relatively early in the year. The use of natural or infrared colour imagery allows for easier identification of land cover, thus significantly reducing the need for follow-up field visits for crop identification.
Community Image Data Portal (CID)
Image acquisition at the JRC
Infrastructure for Spatial Information in the European Community - INSPIRE
Bringing it all together
The JRC is the in-house science service of the European Commission, supporting the policies of the Union with impartial scientific advice. In the environmental domain, it is widely recognised that a key challenge facing humanity is the need to understand and better communicate to all involved the complex relationships between environment and society. Digital Earth is a framework that brings together open data policies, ICT technologies, data, and people to help develop a global shared understanding of these relationships and the consequences of human activity.
The JRC has worked with international partners to develop the vision of Digital Earth. Now it is working towards turning this vision into a reality by building on the achievements of the INSPIRE initiative in Europe, engaging in global efforts such as GEOSS, and developing new projects in the Horizon 2020 research framework that will establish key components of Digital Earth.