Digital Earth 2020:towards the vision for the next decade

This position paper is the outcome of a brainstorming workshop organised by the International Society for Digital Earth(ISDE)in Beijing in March 2011.It argues that the vision of Digital Earth(DE)put forward by Vice-President Al Gore 13 years ago needs to be re-evaluated in the light of the many developments in the fields of information technology,data infrastructures and earth observation that have taken place since.The paper identifies the main policy,scientific and societal drivers for the development of DE and illustrates the multi-faceted nature of a new vision of DE grounding it with a few examples of potential applications.Because no single organisation can on its own develop all the aspects of DE,it is essential to develop a series of collaborations at the global level to turn the vision outlined in this paper into reality.

The Digital Belt and Road program in support of regional sustainability

The Belt and Road initiative has a significant focus on infrastructure,trade,and economic development across a vast region,and it also provides significant opportunities for sustainable development.The combined pressure of climate variability,intensified use of resources,and the fragility of ecosystems make it very challenging,however,to achieve future sustainability.To develop the path in a sustainable way,it is important to have a comprehensive understanding of these issues across nations and evaluate them in a scientific and well-informed approach.In this context,the Digital Belt and Road(DBAR)program was initiated as an international venture to share expertise,knowledge,technologies,and data to demonstrate the role of Earth observation science and technology and big Earth data applications to support large-scale development.In this paper,we identify pressing challenges,present the research priorities and foci of the DBAR program,and propose solutions where big Earth data can make significant contributions.This paper calls for further joint actions and collaboration to build a digital silk road in support of sustainable development at national,regional and global levels.

Current status and future directions of geoportals

Geoportals are a consolidated web-based solution to provide open spatial data sharing and online geo-information management.Their roles and possible advancements according to the Digital Earth vision and implementation require investigations.This paper presents a review of the literature concerning geoportals and serves the following primary purposes.First,various geoportal approaches for discovering and accessing Earth observation data and geo-information,mainly with scientific purposes,are summarized according to their characteristics and functionalities.Second,current major challenges in geoportals are identified in terms of functionalities,technologies,and especially big data support,from geoportal cases of China.Finally,based on lessons learned from the international and Chinese geoportals,solutions and recommendations for the challenges in geoportals are proposed in terms of their architectures,services,and technologies.The results show that geoportals usually provide access to distributed data systems,offering maps,data discovery,and data downloads.Some of them are also capable of offering online analysis and processing service,enhanced semantic search engines,and dynamic visualization tools.The strength of geoportals could lead to a full-fledged online Digital Earth system that could provide better data sharing and dissemination solutions to the challenges posed by big data.

An efficient built-up land expansion model using a modified U-Net

This paper introduces an improved convolutional neural network based on the conventional U-Net for simulating built-up land expansion.The proposed method hires a pixel-wise semantic segmentation approach considering the spatial drivers affecting urbanization as data cubes.Independent variables including altitude,slope,and distance from barren,crop,greenery,roads,and urban areas for 1998,2008,and 2018 were considered as covariates for the simulation of built-up land expansion in Tehran and Karaj regions in Iran.The proposed method was compared with the random forest(RF)algorithm as the baseline model.Evaluation using the area under the total operating characteristic indicated the superiority of our modified U-Net(0.87)over the RF(0.82)algorithm.Furthermore,evaluation using the percent correct metric indicated that our proposed model is capable of learning neighborhood effects effectively leading to simulate built-up land expansion accurately,independent from applying a cellular automata(CA)model.Therefore,the modified U-Net independent from the CA which can consider the neighborhood effects is recommended for the simulation of built-up land expansion precisely.

Remote sensing image fusion: an update in the context of Digital Earth

Remote sensing image fusion has come a long way from research experiments to an operational image processing technology.Having established a framework for image fusion at the end of the 90s,we now provide an overview on the advances in image fusion during the past 15 years.Assembling information about new remote sensing image fusion techniques,recent technical developments and their influence on image fusion,international societies and working groups,and new journals and publications,we provide insight into new trends.It becomes clear that image fusion facilitates remote sensing image exploitation.It aims at achieving better and more reliable information to better understand complex Earth systems.The numerous publications during the last decade show that remote sensing image fusion is a well-established research field.The experiences gained foster other technological developments in terms of sensor configuration and data exploitation.Multi-modal data usage enables the implementation of the concept of Digital Earth.In order to advance in this respect,we recommend that updated guidelines and a set of commonly accepted quality assessment criteria are needed in image fusion.

Perspectives on the nature of geospatial information

1.Introduction In the first issue of this year,our editor-in-chief wrote an inspiring Editorial about the 20 years’history of this jour-nal.That forms a nice background to this Special Issue,in that he gave a very good overview of the journal’s aims and scope,and an interesting summary of geospatial infor-mation science,as well as some challenges for the future.During this 20th anniversary year,we will be producing two Special Issues to mark this auspicious occasion.

Fundamentals of satellite remote sensing:an environmental approach

This is a very useful textbook for university teachers giving undergraduate courses in remote sensing,and for those giving courses on environmental issues.It is written by one of the best known European remote sensing professors.The book consists of nine well-structured chapters,which,together with the more than 30 pages of literature references makes it also an excellent reference for post-graduate students doing research on environmental applications of remote sensing.