Monitoring of the human-induced changes and the availability of reliable and methodologically consistent urban area maps are essential to support sustainable urban development on a global scale. The Global Human Settlement Layer (GHSL) is a project funded by the European Commission, Joint Research Centre, which aims at providing scientific methods and systems for reliable and automatic mapping of built-up areas from remote sensing data. In the frame of the GHSL, the opportunities offered by the recent availability of Sentinel-2 data are being explored using a novel image classification method, called Symbolic Machine Learning (SML), for detailed urban land cover mapping. In this paper, a preliminary test was implemented with the purpose of: (i) assessing the applicability of the SML classifier on Sentinel-2 imagery; (ii) evaluating the complementarity of Sentinel-1 and Sentinel-2; and (iii) understanding the added-value of Sentinel-2 with respect to Landsat for improving global high-resolution human settlement mapping. The overall objective is to explore areas of improvement, including the possibility of synergistic use of the different sensors. The results showed that noticeable improvement of the quality of the classification could be gained from the increased spatial detail and from the thematic contents of Sentinel-2 compared to the Landsat derived product as well as from the complementarity between Sentinel-1 and Sentinel-2 images.
The growth of the built environment is a global environmental change processes that can be measured and monitored with Earth Observation. That growth is expected to continue as populations continue to both increase and urbanize. The Global Human Settlement Layer (GHSL) project was set up to measure and monitor the global built up environment and its changes [1]. The GHSL layers presented herein are derived by processing the global archive of Landsat imagery dating back to 1975. GHSL from Landsat include four global built up information layers corresponding to epochs: 1975, 1990, 2000 and 2014 [2]. The geo-information generated is used in a wide variety of applications that include the generation of urbanization statistics, to quantify exposure to natural hazards for disaster risk and early warning models, to derive global fine scale population density grids, and to generate indicators to monitor targets for main international framework agreements.
1 September 2020 in Transportation Research Part D: Transport and Environment
• Holistic analysis of electric light commercial vehicles for low emission transport. • Total cost of ownership of some electric vehicle variants is already favourable now. • High penetration scenarios decrease CO2 and other emissions by 2030 above 3%. • Electric light commercial vehicles can reduce particulate concentrations by ca. 2%. • Besides fiscal support measures, other policies needed to remove market barriers.
28 October 2010 in IEEE Transactions on Geoscience and Remote Sensing
An important aspect of satellite image time series is the simultaneous access to spatial and temporal information. Various tools allow end users to interpret these data without having to browse the whole data set. In this paper, we intend to extract, in an unsupervised way, temporal evolutions at the pixel level and select those covering at least a minimum surface and having a high connectivity measure. To manage the huge amount of data and the large number of potential temporal evolutions, a new approach based on data-mining techniques is presented. We have developed a frequent sequential pattern extraction method adapted to that spatiotemporal context. A successful application to crop monitoring involving optical data is described. Another application to crustal deformation monitoring using synthetic aperture radar images gives an indication about the generic nature of the proposed approach.
This work introduces a new classification method in the remote sensing domain, suitably adapted to dealing with the challenges posed by the big data processing and analytics framework. The method is based on symbolic learning techniques, and it is designed to work in complex and information-abundant environments, where relationships among different data layers are assessed in model-free and computationally-effective modalities. The two main stages of the method are the data reduction-sequencing and the association analysis. The former refers to data representation; the latter searches for systematic relationships between data instances derived from images and spatial information encoded in supervisory signals. Subsequently, a new measure named the evidence-based normalized differential index, inspired by the probability-based family of objective interestingness measures, evaluates these associations. Additional information about the computational complexity of the classification algorithm and some critical remarks are briefly introduced. An application of land cover mapping where the input image features are morphological and radiometric descriptors demonstrates the capacity of the method; in this instructive application, a subset of eight classes from the Corine Land Cover is used as the reference source to guide the training phase.