Challenges

The world population explosion is accompanied by rapid urbanisation causing urban sprawl. Since 2008, for the first time in the history of humanity, over half the population has been living in an urban environment. In 2050, it is estimated that around 70% of the world’s population will be city-dwellers. This urbanisation will weigh heavily on natural resources globally, with tensions over available land, habitats and biodiversity. Food demands should double, power consumption increase by 80% and water supply needs by 55%… These huge challenges will only be met if efficient cities are planned, capable of synergy between consumption and production. In view of these challenges, it has become vital for numerous operational applications to monitor artificialisation, and to detect and characterise urban change. In such circumstances, remote sensing represents an extraordinary wealth of information.

Satellite images are a source of value-added information (in terms of spatial, temporal and spectral resolution) that needs to be fully exploited today so as to rise to these numerous challenges.

Research issues

Shanghai View

Cities are complex systems and their impact on the environment is measured in various areas such as artificialisation, biodiversity, air and water quality, noise and global warming among others. Through the variety of images available, remote sensing can draw up inventories, perform impact studies, monitor areas or events over time and contribute to territorial planning. The research issues to be explored are both scientific and methodological, and include:

  • Urban sprawl monitoring helps to measure the progression of urban sprawl and to calculate several indicators such as the artificialisation of surfaces or the consumption of agricultural space. The availability of these spatio-temporal indicators can improve the implementation of urban development strategies;
  • Urban morphology characterization and its evolution: the impact of urbanized spaces on radiative and energy exchanges between the urban surface and the urban canopy requires a precise knowledge of the types of surfaces and materials used for constructions. Multispectral or even hyperspectral images with high and very high spatial resolution can provide the information necessary for meteorological models and allow advances in the knowledge of the impacts of the city on its environment;
  • Urban vegetation inventory and species mapping: the issue of urban vegetation has grown considerably in recent years in relation to several themes such as urban biodiversity, the well-being of urban populations, the quality of the living environment and the impact of vegetated areas on the intensity of the urban heat island and, more broadly, on global warming.
  • The inventory and characterization of the issues and exposed elements can be defined by remote sensing for a natural and/or anthropogenic hazard. The identification of structural issues, natural or other amenities within the risk perimeter can enable the implementation of adaptation strategies for these areas.

Involved SECs

Land cover SEC

Presentation The Scientific Expertise Centre “Land Cover SEC” brings together teams from Cesbio, UMR Ispa, Dynafor, CNRM, UMR Tetis, IGN–Matis, […]

Senegal-Rift-Fever-Map

Risks associated with infectious diseases SEC

Developing transmission risk maps for the various infectious diseases, vector-borne or otherwise, using Earth Observation data.

Surface Temperature and Emissivity SEC

Improving estimation and mapping for land surface temperature and emissivity.

Urban Strasbourg

Urban SEC

Presentation The “Urbanisation and Artificialisation” Scientific Expertise Centre (SEC) brings together teams from  Live – Univ. de Strasbourg, LETG-Rennes, IGN-LaSTIG – Univ. […]

Applications

Current projects

  • The LIVE-led ANR TIMES project “Exploitation of high temporal frequency heterogeneous data masses for the analysis of environmental change” (2017-2021), whose objectives are to generate new knowledge on environmental dynamics from the exploitation of massive and heterogeneous geospatial data. The aim is to propose and develop new methods for exploiting complementarity and, above all, high temporal frequency, particularly Sentinel images, in order to respond to societal and environmental issues, particularly in urban areas.
  • The TOSCA project ‘Artificialization – Urbanization’ (2016-2018) aimed to federate laboratories working on urban issues in order to support the activities of the Urban CES. Thus, this project allowed (i) to develop the use of remote sensing tools, methods and data applied to this issue, and (ii) to enhance and qualify the information and promote its appropriation by the users. From an application point of view, the stakes are to ensure knowledge of the consumption of artificial surfaces for land management, in particular by producing national and updated maps of artificial spaces, maps of urban fabrics, but also of ‘green’ surfaces in urban areas.
  • The Action 7 Project of the National Biodiversity Plan (UMR Tetis, IGN), led by the French Ministry of Ecological Transition and Solidarity, brings together three public bodies (IGN, Cerema and Irstea). The objective, as defined in action 7, is to “[publish], every year, an inventory of land consumption and [make] transparent and comparable data available to territories and citizens at all territorial scales”.
  • The Artisols Project (UMR Tetis), an ERDF project that brings together various public (Region, DRAAF, Irstea, Inra, Ensat) and private (BRL) partners in Occitanie. It aims to produce methods and spatialized indicators to monitor artificialisation in the new region and measure its impact in terms of consumption of land with agronomic potential.
  • The URCLIM Project (ERA4CS, JPI Climate 2017-2020) – URban CLIMate services is a multidisciplinary research project dedicated to the realization of integrated Urban Climate Services (UCS) dedicated in particular to urban planning. This project aims in particular to develop a methodology for the creation of high spatial resolution maps of urban parameters useful for climate studies. These maps will be created both from existing geographic databases and from information extracted by remote sensing. URCLIM also aims to analyse the propagation of uncertainty in climate models from the regional to the city scale, but also in an even more localised manner for impact studies.

Past project

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  • VEGIDAR TOSCA project (2015-2016) – Vegetation in urban areas by coupling very high spatial resolution optical remote sensing and LiDAR . This project aimed at exploiting LiDAR and multi-angular PLEIADES data to characterize as finely as possible the vegetation in urban environments.
  • HYEP project (ANR 2014-2018) – Hyperspectral Imagery for Environmental Planning is a research project aimed at evaluating the contribution of hyperspectral imagery to the analysis of urban environments. Methodological developments have been carried out in order to remove various obstacles at different stages of the image processing chain (atmospheric corrections, fusion between hyperspectral, multispectral and panchromatic images, classification, blending). A morpho-spectral database specifically dedicated to the urban environment was created within the framework of the project. Finally, in order to propose specifications for a satellite mission, HYEP then includes a comparison and evaluation of the spectral and spatial configurations of different sensors in order to extract different information (materials, vegetation) finely describing the city.
  • PAYTAL project (Paysage et étalement urbain: dynamiques physique et culturelle et modélisation – Landscape and urban sprawl: physical and cultural dynamics, modelling) (2011-2014): this project was designed to study the relationship between urban sprawl and the changing landscape. Its multidisciplinary approache aimed to couple economic analysis methods (urban economics), spatial methods (geomatics and remote sensing) and landscape perceptions. Using computer tools (data mining and classification), the project aimed to accurately describe the morphology of urban sprawl and landscape dynamics.
  • From a methodological viewpoint, the COCLICO project (COllaboration, CLassification, Incrémentalité et COnnaissances – Collaboration, classification, incrementality and knowledge) (2012-2016) aims to propose a generic, innovative method for the multi-scale analysis of large volumes of spatio-temporal data guided by knowledge of a particular theme, especially in the urban environment. Data mining appears an appropriate solution for choosing the methods and parameters to use in a processing chain from raw data to knowledge 
    More information on the COCLICO project
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Doctoral Theses

  • Analyse de séries temporelles massives d’images satellitaires pour le suivi de la dynamique des modes d’occupation des sols
    Romain Wenger
    Thèse en cours –  LIVE CNRS UMR 7362 – Université de Strasbourg
  • Apport des données de télédétection à très haute résolution spatiale pour la cartographie de la végétation en milieu urbain : application à Rennes Métropole
    Jean Nabucet
    2018 – Thèse LETG-Rennes
  • Télédétection par analyse de retours d’onde LIDAR et spectrométrie à haute résolution des zones sensibles en environnement côtier et urbain
    Antoin Ba
    2017 – Thèse LETG-Rennes
  • Apport des images satellites à très haute résolution spatiale couplées à des données géographiques multi-sources pour l’analyse des espaces urbains
    Simon Rougier
    2016 – Thèse LIVE CNRS UMR 7362 – Université de Strasbourg