Showing papers in "International Journal of Digital Earth in 2011"
TL;DR: In this paper, the authors propose a cloud-based infrastructure for the geospatial sciences that can support discovery, access and utilization of data and data processing so as to relieve scientists and engineers of IT tasks and focus on scientific discoveries.
Abstract: The geospatial sciences face grand information technology (IT) challenges in the twenty-first century: data intensity, computing intensity, concurrent access intensity and spatiotemporal intensity. These challenges require the readiness of a computing infrastructure that can: (1) better support discovery, access and utilization of data and data processing so as to relieve scientists and engineers of IT tasks and focus on scientific discoveries; (2) provide real-time IT resources to enable real-time applications, such as emergency response; (3) deal with access spikes; and (4) provide more reliable and scalable service for massive numbers of concurrent users to advance public knowledge. The emergence of cloud computing provides a potential solution with an elastic, on-demand computing platform to integrate – observation systems, parameter extracting algorithms, phenomena simulations, analytical visualization and decision support, and to provide social impact and user feedback – the essential eleme...
326 citations
TL;DR: This mapping attempt demonstrates that training/validation data accumulation from different mapping projects must be promoted to support future global land cover mapping.
Abstract: Global land cover is one of the fundamental contents of Digital Earth. The Global Mapping project coordinated by the International Steering Committee for Global Mapping has produced a 1-km global l...
163 citations
TL;DR: A time series of vegetation activity at 10-daily time steps between 1998 and 2008 covering large parts of South America at 1 km spatial resolution is described and the Whittaker smoother was applied to a SPOT VGT time series.
Abstract: It is widely accepted that natural resources should only be sustainably exploited and utilized to effectively preserve our planet for future generations. To better manage the natural resources, and to better understand the closely linked Earth systems, the concept of Digital Earth has been strongly promoted since US Vice President Al Gore's speech in 1998. One core element of Digital Earth is the use and integration of remote sensing data. Only satellite imagery can cover the entire globe repeatedly at a sufficient high-spatial resolution to map changes in land cover and land use, but also to detect more subtle changes related for instance to climate change. To uncover global change effects on vegetation activity and phenology, it is important to establish high quality time series characterizing the past situation against which the current state can be compared. With the present study we describe a time series of vegetation activity at 10-daily time steps between 1998 and 2008 covering large part...
154 citations
TL;DR: The European Digital Archive of Soil Maps (EuDASM), through which all archived paper maps of ISRIC has been made accessible to the public through the Internet, is created, to transfer paper-based soil maps into a digital format with the maximum possible resolution and to ensure their preservation and easy disclosure.
Abstract: Historical soil survey paper maps are valuable resources that underpin strategies to support soil protection and promote sustainable land use practices, especially in developing countries where digital soil information is often missing. However, many of the soil maps, in particular those for developing countries, are held in traditional archives that are not easily accessible to potential users. Additionally, many of these documents are over 50 years old and are beginning to deteriorate. Realising the need to conserve this information, the Joint Research Centre (JRC) and the ISRIC-World Soil Information foundation have created the European Digital Archive of Soil Maps (EuDASM), through which all archived paper maps of ISRIC has been made accessible to the public through the Internet. The immediate objective is to transfer paper-based soil maps into a digital format with the maximum possible resolution and to ensure their preservation and easy disclosure. More than 6,000 maps from 135 countries ha...
108 citations
TL;DR: It is concluded that LSU and MTMF are suitable for sub-pixel mapping of alteration minerals and when the purpose is identification of particular targets, rather than all the elements in the scene, the M TMF algorithm could be proposed.
Abstract: This paper is an attempt to introduce the role of earth observation technology and a type of digital earth processing in mineral resources exploration and assessment. The sub-pixel distribution and quantity of alteration minerals were mapped using linear spectral unmixing (LSU) and mixture tuned matched filtering (MTMF) algorithms in the Sarduiyeh area, SE Kerman, Iran, using the visible-near infrared (VNIR) and short wave infrared (SWIR) bands of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument and the results were compared to evaluate the efficiency of methods. Three groups of alteration minerals were identified: (1) pyrophylite-alunite (2) sericite-kaolinite, and (3) chlorite-calcite-epidote. Results showed that high abundances within pixels were successfully corresponded to the alteration zones. In addition, a number of unreported altered areas were identified. Field observations and X-ray diffraction (XRD) analysis of field samples confirmed the dominant mineral p...
77 citations
TL;DR: Examining 33 grassland water points using vegetation field studies and remote sensing techniques to track desertification on the Mongolian plateau established a significant correlation between same-year field observation and NDVI data, enabling an historical land cover perspective to be developed from 1998 to 2006.
Abstract: Changing environmental and socio-economic conditions make land degradation, a major concern in Central and East Asia. Globally satellite imagery, particularly Normalized Difference Vegetation Index...
71 citations
TL;DR: The study results showed that the soil moisture content was the most effective actor on the vegetative cover, LST, and drought status in the study area.
Abstract: Iraq has suffered severely from drought in recent years and the year 2008 was the driest, particularly in the Iraqi Kurdistan region. This study incorporated Geoinformation technology into mapping the drought that severely affected the Kurdistan region in the years 2007–2008. Geoinformation technology provides support in the theories, methods and techniques for building, and development of Digital Earth aspect. Five vegetation, soil, water, and land surface temperature (LST) indices were applied to two Landsat 7 ETM+ imageries of June 2007 and June 2008, to assess the drought impacts in Erbil governorate Kurdistan during the study period. The indices that were employed in this study were Normalized Difference Vegetation Index, Bare Soil Index, Normalized Differential Water Index, Tasseled Cap Transformation Wetness, and LST. The results revealed a significant decrease in the vegetative cover (56.7%) and a decline in soil/vegetation wetness (29.9%) of the total study area. Likewise, there was a si...
63 citations
TL;DR: This study determined the optimal parameters for calculating a DTM by using an iterative algorithm to select minimum elevations from LiDAR data in a steep mountain area with shrub vegetation, and the parameters were: input data type, analysis window size, and height thresholds.
Abstract: The creation of a quality Digital Terrain Model (DTM) is essential for representing and analyzing the Earth in a digital form. The continuous improvements in the acquisition and the potential of airborne Light Detection and Ranging (LiDAR) data are increasing the range of applications of this technique to the study of the Earth surface. The aim of this study was to determine the optimal parameters for calculating a DTM by using an iterative algorithm to select minimum elevations from LiDAR data in a steep mountain area with shrub vegetation. The parameters were: input data type, analysis window size, and height thresholds. The effects of slope, point density, and vegetation on DTM accuracy were also analyzed. The results showed that the lowest root mean square error (RMSE) was obtained with an analysis window size of 10 m, 5 m, and 2.5 m, rasterized data as input data, and height thresholds equal to or greater than 1.5 m. These parameters showed a RMSE of 0.19 m. When terrain slope varied from 0–10% to 50...
52 citations
TL;DR: An integrated platform has been developed by the WestDC, and this has the function of data sharing, acting as a knowledge repository, and highlights include detailed data documentation, the integration of data with bibliographic knowledge, data publishing, and data reference.
Abstract: Sharing of scientific data can help scientific research to flourish and facilitate more widespread use of scientific data for the benefit of society. The Environmental and Ecological Science Data Center for West China (WestDC), sponsored by the National Natural Science Foundation of China (NSFC), aims to collect, manage, integrate, and disseminate environmental and ecological data from western China. It also aims to provide a long-term data service for multidisciplinary research within NSFC's “Environment and Ecology of West China Research Plan” (NSFC West Plan). An integrated platform has been developed by the WestDC, and this has the function of data sharing, acting as a knowledge repository. Major data sets developed by the WestDC include basic geographic data, the regionalization of global data set for China, scientific data for cold and arid regions in China, scientific data for the cryosphere in countries that neighbor China, data relating to the inland river basins in northwestern China, a...
40 citations
TL;DR: In this paper, a straightforward approach for flood area mapping in a transboundary riverbed using Geographic Object-Based Image Analysis (GOIA) was developed and validated for delineation.
Abstract: The aim of this study was to develop a straightforward approach for flood area mapping in a transboundary riverbed using Geographic Object-Based Image Analysis. Weak bilateral/multilateral cooperation among neighboring countries hampers effective disaster management and mitigation activities over transboundary areas and strengthens the demand for reliable remote-sensing-derived information. Three object-based classification approaches using ENVISAT/ASAR and multi-temporal LANDSAT TM data were developed and validated for flood area delineation. The accuracy assessment of the classification results was based on oblique air photo interpretation and an area-based comparison with the official flood map. The bi-level object-based model using the Normalized Difference Water Index and the original post-flood TM bands attained 92.67% overall accuracy in inundated-areas detection, while the ENVISAT/ASAR classification was the least accurate (85.33%), probably due to the lower spatial resolution of the Synthetic Ape...
40 citations
TL;DR: The paper identifies opportunities and synergies with the current policy priorities in Europe (Europe 2020, Innovation Union and Digital Agenda) and highlights a number of key areas to advance the development of DE from a European perspective.
Abstract: The purpose of this paper is to contribute to the definition of a European perspective on Digital Earth (DE), identify some actions that can contribute to raise the awareness of DE in the European context and thus strengthen the European contribution to the International Society for Digital Earth (ISDE). The paper identifies opportunities and synergies with the current policy priorities in Europe (Europe 2020, Innovation Union and Digital Agenda) and highlights a number of key areas to advance the development of DE from a European perspective: (1) integrating scientific research into DE; (2) exploiting the Observation Web with human-centred sensing; and (3) governance, including the establishment of stronger linkages across the European landscape of funding streams and initiatives. The paper is offered also as a contribution to the development of this new vision of DE to be presented at the next International DE Conference in Perth, Australia, in August 2011. The global recognition of this new vi...
TL;DR: A real-time algorithm for viewshed analysis in 3D scenes is presented by using the parallel computing capabilities of a graphics processing unit (GPU), in contrast to traditional algorithms based on line-of-sight.
Abstract: Spatial analysis, including viewshed analysis, is an important aspect of the Digital Earth system. Viewshed analysis is usually performed on a large scale, so efficiency is important in any Digital Earth application making these calculations. In this paper, a real-time algorithm for viewshed analysis in 3D scenes is presented by using the parallel computing capabilities of a graphics processing unit (GPU). In contrast to traditional algorithms based on line-of-sight, this algorithm runs completely within the programmable 3D visualization pipeline to render 3D terrains with viewshed analysis. The most important difference is its integration of the viewshed calculation with the rendering module. Invisible areas are rendered as shadows in the 3D scene. The algorithm process is paralleled by rasterizer units in the graphics card and by vertex and pixel shaders executed on the GPU. We have implemented this method in our 3D Digital Earth system with the DirectX 9.0c API and tested on some consumer-level PC plat...
TL;DR: The FRA RSS Landsat dataset was evaluated to assess overall quality and quantify potential limitations, and an operational algorithm for Landsat data pre-processing, normalization, and cloud detection was created and implemented.
Abstract: To collect and provide periodically updated information on global forest resources, their management and use, the United Nations Food and Agriculture Organization (FAO) has been coordinating global...
TL;DR: It is found that standing snow is inversely related to coherence in the Himalayan region, which indicates massive snowfall in the region in the winter season and melting in the summer.
Abstract: Information of snow cover (SC) over Himalayan regions is very important for regional climatological and hydrological studies. Precise monitoring of SC in the Himalayan region is essential for water...
TL;DR: Digital Africa's first priority could be to harness continent-wide and national data as well as local information resources, collected by citizens, in order to monitor, measure and forecast MDGs.
Abstract: Several innovative ‘participatory sensing’ initiatives are under way in East Africa. They can be seen as local manifestations of the global notion of Digital Earth. The initiatives aim to amplify t...
TL;DR: Low-Cost Mobile Mapping System (LCMMS) as mentioned in this paper was deployed in Port-au-Prince (Haiti) and tested during a five-day survey in February-March 2010.
Abstract: Among the major natural disasters that occurred in 2010, the Haiti earthquake was a real turning point concerning the availability, dissemination and licensing of a huge quantity of geospatial data. In a few days several map products based on the analysis of remotely sensed data-sets were delivered to users. This demonstrated the need for reliable methods to validate the increasing variety of open source data and remote sensing-derived products for crisis management, with the aim to correctly spatially reference and interconnect these data with other global digital archives. As far as building damage assessment is concerned, the need for accurate field data to overcome the limitations of both vertical and oblique view satellite and aerial images was evident. To cope with the aforementioned need, a newly developed Low-Cost Mobile Mapping System (LCMMS) was deployed in Port-au-Prince (Haiti) and tested during a five-day survey in February–March 2010. The system allows for acquisition of movies and single ge...
TL;DR: Advances in Environmental Remote Sensing: Sensors, Algorithms, and Applications, by Q. Weng, CRC Press, Taylor & Francis Group, Boca Raton, USA, 2011, 556 pp.
Abstract: Advances in Environmental Remote Sensing: Sensors, Algorithms, and Applications, by Q. Weng, CRC Press, Taylor & Francis Group, Boca Raton, USA, 2011, 556 pp., (hardback), ISBN 978-1-4200-9175-5 Th...
TL;DR: This paper presents the results of the application of mathematical morphology for the automatic quantification of the number of tents and the detection of changes in the Menik Farm IDP camp in Sri Lanka, using morphological image processing techniques and previously specified criterion.
Abstract: This paper presents the results of the application of mathematical morphology for the automatic quantification of the number of tents and the detection of changes in the Menik Farm IDP camp in Sri Lanka. The tents were retrieved using an area-constraint top-hat opening applied to WorldView-1 data. The counting of tents was based on the centroids of the automatically detected structures indicating an overall number of 25,150 tents on the 26 June 2009. The comparison with a visual interpretation produced an R 2 of 0.97 with an error of 1.25%. In addition, an automated detection of changes inside a camp area was conducted. The comparison of the satellite image of 26 June 2009 (WorldView-1) and an image of 28 February 2010 (GeoEye-1) is based on mutual (mixed) information metric, after using morphological image processing techniques and previously specified criterion. Changes are observed on a terrain of around 15.2% of the total camp area and 3813 of previously detected structures disappeared in a period of ...
TL;DR: The quality control, validation and verification of the European Flood Alert System (EFAS), designed as a flood early warning system at pan-European scale, to complement national systems and provide flood warnings more than 2 days before a flood, are described.
Abstract: The quality control, validation and verification of the European Flood Alert System (EFAS) are described. EFAS is designed as a flood early warning system at pan-European scale, to complement national systems and provide flood warnings more than 2 days before a flood. On average 20–30 alerts per year are sent out to the EFAS partner network which consists of 24 National hydrological authorities responsible for transnational river basins. Quality control of the system includes the evaluation of the hits, misses and false alarms, showing that EFAS has more than 50% of the time hits. Furthermore, the skills of both the meteorological as well as the hydrological forecasts are evaluated, and are included here for a 10-year period. Next, end-user needs and feedback are systematically analysed. Suggested improvements, such as real-time river discharge updating, are currently implemented.
TL;DR: Two remote-sensing methods, Surface Energy Balance Algorithms for Land (SEBAL) and Vegetation Index/Temperature Trapezoid (VITT), for ET estimation from terrestrial GDEs demonstrate that even a simple physical ET model can provide useful information for groundwater management, and more broadly other applications in hydrologic modelling and digital earth studies.
Abstract: Understanding and mitigating against the impact of groundwater extraction on groundwater-dependent ecosystems (GDE) requires information of evapotranspiration (ET) of these ecosystems. In this pilot study, we tested two remote-sensing methods, Surface Energy Balance Algorithms for Land (SEBAL) and Vegetation Index/Temperature Trapezoid (VITT), for ET estimation from terrestrial GDEs. Multi-temporal Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM + ) images were used to derive vegetation indices and land surface temperatures for ET estimation. Radiative transfer model was used for atmospheric correction of the Landsat images. Field measurements were used to validate the remote sensing estimation of VI and surface temperature. Both methods have been implemented in a geographic information system (GIS) using automated scripts and ancillary GIS data for quality control process. Comparison of predicted ET by SEBAL to VITT model indicates relatively good agreement (R 2>0.90) and promise ...
TL;DR: The technical framework of the CDOPS is discussed, including its data, function, and application layers, and two key technologies are studied in detail that will enable the construction of the 3D ocean environment and the visualization of the ocean model output data.
Abstract: Digital Ocean is a new research domain of Digital Earth. Because of the spatio-temporal, three-dimensional (3D) and intrinsically dynamic nature of ocean data, it is more difficult to make a breakt...
TL;DR: Derivative landscape analysis outputs from the S RTM-DEM suggest the wide acceptability and applicability of the freely available SRTM data source, especially in the regional scale applications related to hydrological modelling, terrain characterisation, disaster management and land degradation studies.
Abstract: Geomorphologic and hydrologic research heavily depends on digital elevation models (DEM) which are currently being prepared from digital contours. The present study examines the use and applicability of freely available global elevation data source (3 arc seconds finished Shuttle Radar Topography Mission (SRTM)) in landform characterisation, geomorphometry, river basin studies and other allied scientific applications in comparison with contour elevation data derived from the surveyed topographical sheets. The relief data extracted from a conventionally digitised geo-information science dataset of topographic contours (1:50,000) are compared with the SRTM-DEM and the variations are analysed. The automated geomorphometric and landform parameters derived from the contour DEM and the computed statistical properties of those parameters have substantial agreement with the same parameters derived from the SRTM-DEM. At the same time, localised variations also exist in some spatial domains. Derivative lan...
TL;DR: Digital remote sensing data of the Indian Remote Sensing satellite series I-D (LISS III, 2006–2007) on 1:50,000 scale, Survey of India (SOI) toposheet of 1914 and 1967 have been utilized to map various land use/land cover changes.
Abstract: Land use and land cover change, perhaps the most significant anthropogenic disturbance to the environment, mainly due to rapid urbanization/industrialization and large scale agricultural activities...
TL;DR: A new method for retrieving Open Geospatial Consortium (OGC) Web Service (OWS) that deals with this challenge using page crawling, link detection, service capability matching, and ontology reasoning, is described in this paper.
Abstract: Finding the right spatially aware web service in a heterogeneous distributed environment using criteria such as service type, version, time, space, and scale has become a challenge in the integration of geospatial information services. A new method for retrieving Open Geospatial Consortium (OGC) Web Service (OWS) that deals with this challenge using page crawling, link detection, service capability matching, and ontology reasoning, is described in this paper. Its major components are distributed OWS, the OWS search engine, the OWS ontology generator, the ontology-based OWS catalog service, and the ontology-based multi-protocol OWS client. Experimental results show that the execution time of this proposed method equals only 0.26 of that of Nutch's method. In addition, the precision is much higher. Moreover, this proposed method can carry out complex OWS reasoning-based queries. It is being used successfully for the Antarctica multi-protocol OWS portal of the Geo-Information Web Service Portal of the Polar.
TL;DR: From experiments on the prototype system, it can be concluded that the parallel system has better efficiency and performance than the conventional system on certain selected modules.
Abstract: In response to the problem of how to give geographic information system (GIS) high-performance capabilities for certain specific GIS applications, a new GIS research direction, parallel GIS processing, has emerged. However, traditional research has focused mostly on implementing typical GIS parallel algorithms, with little discussion of how to parallelize an entire GIS package on clusters based on theory. Therefore, the authors have chosen the geographic resources analysis support system (GRASS) GIS as the object of their research and have put forward the concept of a cluster-based open-source parallel GIS (cluster-based OP-GIS) as a tool to support Digital Earth construction. The related theory includes not only the parallel computing mode, architecture, and software framework of such a system, but also various parallelization patterns. From experiments on the prototype system, it can be concluded that the parallel system has better efficiency and performance than the conventional system on cert...
TL;DR: A fine-scale population density map is presented as an example of a situation in which reference data on a statistical sample cannot be collected.
Abstract: An optimal validation of a thematic map would ideally require in-situ observations of a large sample of units specifically conceived for the map under validation. This is often not possible due to budget limitations. The alternative can be using photo-interpretation of high or very high resolution images instead of in-situ observations or using available data sets that do not fully comply with the ideal characteristics: unit size, reference date or sampling plan. This paper illustrates some examples of use of available data in the European Union. For land cover maps, the best existing data set is probably Land Use/Cover Area-frame Survey (LUCAS) that has been conducted by Eurostat on four occasions since 2001. Because LUCAS is based on systematic sampling, advantages and limitations of systematic sampling are discussed. A fine-scale population density map is presented as an example of a situation in which reference data on a statistical sample cannot be collected.
TL;DR: A framework combining remote sensing and GIS-cellular automata (CA) concepts aimed at improving the modeling of unauthorized land use sprawl can lead to new levels of understanding of how urban areas grow and change as in view of digital earth aspiration.
Abstract: The paper explores a framework combining remote sensing and GIS-cellular automata (CA) concepts aimed at improving the modeling of unauthorized land use sprawl. Remote sensing data have been used i...
TL;DR: In order to overcome problems of legibility, urban block areas are enlarged through amalgamation and the intervening roads in the amalgams are eliminated and a simpler and more legible road network has been acquired.
Abstract: When road symbols are shown in a size proportionate to the reduced scale, several problems of legibility may arise concerning the urban blocks. By the method proposed in this paper, in order to overcome these problems, urban block areas are enlarged through amalgamation and the intervening roads in the amalgams are eliminated. This method includes two new approaches for computation of threshold used in determination of important roads based on the connectivity measure, and for definition of minimum block space and area requirements based on graphic limits. A block life cycle was designed for amalgamation of blocks. For the amalgamation process, a new algorithm was developed. The experimental testing indicates that important roads and the roads surrounding the urban area have been preserved. A simpler and more legible road network has been acquired. This method can be described as a more holistic approach as the buildings are taken into account. The problems arising in the experimental testing ind...
TL;DR: In this paper, Vosselman et al. present a survey of the state-of-the-art in airborne and terrestrial laser scanning, with a focus on the first-person laser scanning.
Abstract: Airborne and terrestrial laser scanning, edited by G. Vosselman and H-G. Maas, Boca Raton, London, New York, CRC Press, Taylor and Francis Group, 2010, xxiv + 311 pp., ISBN 978-1904445-87-6 This is...
TL;DR: A scalable virtual learning environment of the Chinese University of Hong Kong is introduced; an explicitly geographical, immersive, and sharable 3D learning space with comprehensive social elements characterized by multi-user collaborative modeling, group learning approaches of geo-collaboration, social space-oriented hierarchical avatars, and knowledge exchanging and sharing based on virtual geographic experiments.
Abstract: This paper introduces a scalable virtual learning environment of the Chinese University of Hong Kong; an explicitly geographical, immersive, and sharable 3D learning space with comprehensive social elements. It is characterized by multi-user collaborative modeling, group learning approaches of geo-collaboration, social space-oriented hierarchical avatars, and knowledge exchanging and sharing based on virtual geographic experiments. Applications for the purpose of public education and virtual geographic experiment, and indicated future works prove the possibility to offer a greater opportunity to foster interdisciplinary collaborations, revitalize teaching patterns and learning contents, improve learners' cognitive abilities to solve problems, and enhance their understanding of scientific concepts and processes.