References of "Binard, Marc"
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See detailAssessing urbanisation effects on rainfall-runoff using a remote sensing supported modelling strategy
Verbeiren, Boud; Van de Voorde, Tim; Canters, Frank et al

in International Journal of Applied Earth Observation and Geoinformation (2013), 21

This paper aims at developing a methodology for assessing urban dynamics in urban catchments and the related impact on hydrology. Using a multi-temporal remote sensing supported hydrological modelling ... [more ▼]

This paper aims at developing a methodology for assessing urban dynamics in urban catchments and the related impact on hydrology. Using a multi-temporal remote sensing supported hydrological modelling approach an improved simulation of runoff for urban areas is targeted. A time-series of five medium resolution urban masks and corresponding sub-pixel sealed surface proportions maps was generated from Landsat and SPOT imagery. The consistency of the urban mask and sealed surface proportion timeseries was imposed through an urban change trajectory analysis. The physically based rainfall-runoff model WetSpa was successfully adapted for integration of remote sensing derived information of detailed urban land use and sealed surface characteristics. A first scenario compares the original land-use class based approach for hydrological parameterisation with a remote sensing sub-pixel based approach. A second scenario assesses the impact of urban growth on hydrology. Study area is the Tolka River basin in Dublin, Ireland. The grid-based approach of WetSpa enables an optimal use of the spatially distributed properties of remote sensing derived input. Though change trajectory analysis remains little used in urban studies it is shown to be of utmost importance in case of time series analysis. The analysis enabled to assign a rational trajectory to 99% of all pixels. The study showed that consistent remote sensing derived land-use maps are preferred over alternative sources (such as CORINE) to avoid over-estimation errors, interpretation inconsistencies and assure enough spatial detail for urban studies. Scenario 1 reveals that both the class and remote sensing sub-pixel based approaches are able to simulate discharges at the catchment outlet in an equally satisfactory way, but the sub-pixel approach yields considerably higher peak discharges. The result confirms the importance of detailed information on the sealed surface proportion for hydrological simulations in urbanised catchments. In addition a major advantage with respect to hydrological parameterisation using remote sensing is the fact that it is site- and period-specific. Regarding the assessment of the impact of urbanisation (scenario 2) the hydrological simulations revealed that the steady urban growth in the Tolka basin between 1988 and 2006 had a considerable impact on peak discharges. Additionally, the hydrological response is quicker as a result of urbanisation. Spatially distributed surface runoff maps identify the zones with high runoff production. It is evident that this type of information is important for urban water management and decision makers. The results of the remote sensing supported modelling approach do not only indicate increased volumes due to urbanisation, but also identifies the locations where the most relevant impacts took place. [less ▲]

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See detailActes de la Conférence internationale de Géomatique et Analyse Spatiale 2012
Billen, Roland ULg; Binard, Marc ULg; Hallot, Pierre ULg et al

Book published by Unité de Géomatique (2012)

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See detailReference visualization and download analysis of the “geographical literature” in the Open Repository of ULg (ORBi)
Stirbu, Simona ULg; Thirion, Paul ULg; Schmitz, Serge ULg et al

Poster (2012, May)

Set up by the University of Liège, ORBi (Open Repository and Bibliography) knew a lightning increase of the online posted references since its creation in 2008. The official launch took place on November ... [more ▼]

Set up by the University of Liège, ORBi (Open Repository and Bibliography) knew a lightning increase of the online posted references since its creation in 2008. The official launch took place on November 26th, 2008 and after considerable efforts on behalf of the team which manages the tool, and researchers who introduce themselves their publications, the contents of the repository managed to reach a value of 64245 references among which 38670 with full text. Working for the Library of Geography of the University of Liege, I found interesting to analyze the number of visualizations and downloads of the references (2005 to 2007) posted online by the ULg geographer’s, and the population interested in this literature. The highlight is on WHO and WHERE are the internet users visualizing and downloading ORBi references from? In order to detect the population using this scientific literature, we analyzed the user IP and their distribution in the world. The data was obtained from a MaxMind database. The type of population using this scientific literature: researchers, individuals, public or private companies was also determined. [less ▲]

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See detailPredicting the spatial distribution of population based on impervious surface maps and modeled land use change
Cornet, Yves ULg; Binard, Marc ULg; Ledant, Martin et al

in Perakis, Konstantinos G.; Moysiadis, Athanasios K. (Eds.) European Association of Remote Sensing Laboratories 32nd EARSeL Symposium Proceedings Advances in Geosciences Mykonos Island, Greece, 21 May - 24 May 2012 (2012)

Land use and changes in the spatial distribution of population are spatially and temporally linked and have an obvious impact on the urban environment. For instance, they influence the mobility and ... [more ▼]

Land use and changes in the spatial distribution of population are spatially and temporally linked and have an obvious impact on the urban environment. For instance, they influence the mobility and accessibility and play an important role in waste water management. This forecasting of the spatial distribution of population is thus a critical issue in planning. In order to allow this forecasting we have adjusted a multiple regression model to estimate the population distribution in function of land-use. The originality in our modeling strategy is the use of sealed surface proportion maps as weighting factor assuming that sealed surface proportion is a proxy of population density. The data exploited to adjust the parameters of the model are three time-series of landuse maps from the EU-MOLAND, census data and medium and high resolution remotely sensed images. We made use of these images in a spectral unmixing procedure that provides the sealed surface proportion maps. In the model, the population was normalized in order to get a model that is independent of time and space. This is required for prediction and spatial extrapolation which assumes a temporally and spatially stable relationship between land use, imperviousness and population density. We validated the model by means of a population disaggregation/re-aggregation procedures and tested its robustness regarding the resolution because predicted sealed surface proportion and predicted landuse maps using the calibrated EU-MOLAND model are generated at lower resolution (200 m) than the resolution used in the model adjustment. The results described in this paper regard the urban zone of Dublin. [less ▲]

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See detailAnnexe 3 – Les circonscriptions électorales depuis 1830
Dodeigne, Jérémy ULg; Binard, Marc ULg

in Bouhon, Frédéric; Reuchamps, Min (Eds.) Les systèmes électoraux de la Belgique (2012)

Electoral districts are not neutral. They reflect political competition as well as they directly influence it.This chapter gives an overview of the redrawing of national electoral districts at the Chamber ... [more ▼]

Electoral districts are not neutral. They reflect political competition as well as they directly influence it.This chapter gives an overview of the redrawing of national electoral districts at the Chamber of Representatives and the Senate since 1830 to 2012 (including the new electoral law for the 'sensitive case' in Belgian politics of the Brussels-Hal-Vilvorde electoral district ). With the process regionalisation and the introduction of regional and community parliaments in the 1970s and the 1980s, the chapter also presents the evolution of electoral districts for the direct elections in the subnational assemblies. Overall, the different maps presented in this work particularly underline the growing magnitude of the electoral districts over times - at both levels of government. [less ▲]

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See detailA Remote Sensing Based Calibration Framework for the MOLAND Urban Growth Model of Dublin
Van de Voorde, Tim; van der Kwast, Johannes; Canters, Frank et al

in International Journal of Agricultural and Environmental Information Systems (2012), 3(2), 1-21

Land-use change models are useful tools for assessing and comparing the environmental impact of alternative policy scenarios. Their increasing popularity as spatial planning instruments also poses new ... [more ▼]

Land-use change models are useful tools for assessing and comparing the environmental impact of alternative policy scenarios. Their increasing popularity as spatial planning instruments also poses new scientific challenges, such as correctly calibrating the model. The challenge in model calibration is twofold: obtaining a reliable and consistent time series of land-use information and finding suitable measures to compare model output to reality. Both of these issues are addressed in this paper. The authors propose a model calibration framework that is supported by information on urban form and function derived from medium-resolution remote sensing data through newly developed spatial metrics. The remote sensing derived maps are compared to model output of the same date for two model scenarios using well-known spatial metrics. Results demonstrate a good resemblance between the simulation output and the remote sensing derived maps. [less ▲]

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See detailMultiparametric observations and analysis in the Bay of Calvi (Corsica), an ideal site for studying the human activity effects and climate changes in the Mediterranean Sea; STARESO
Gobert, Sylvie ULg; Alvera Azcarate, Aïda ULg; Barth, Alexander ULg et al

Conference (2010, May)

STARESO (Station de REcherche Sous marine et Océanographique) is the marine and oceanographic research station of the University of Liège (Belgium) managed by the French company STARESO S.A.. Constructed ... [more ▼]

STARESO (Station de REcherche Sous marine et Océanographique) is the marine and oceanographic research station of the University of Liège (Belgium) managed by the French company STARESO S.A.. Constructed in 1969, it is located near Calvi (Corsica, Western Mediterranean Sea) in an oligotrophic area chosen for the exceptional quality of its coastal waters STARESO offers to the oceanographers, by diving or with boats, a direct access to the sea. The variety of the accessible ecosystems is remarkable and unique in the Mediterranean basin: -the Bay of Calvi is characterized by healthy and very diverse biocenosis (e.g. Posidonia meadows, rocky and sandy communities, -a steep submarine canyon, with depths greater than 1 000 meters, is accessible in 15 minutes of navigation; -the Liguro-Provençal front, a major hydrologic structure, is situated between 10 and 15 miles of the coast. STARESO is accessible all the year for everybody and is functioning like an oceanographic research vessel. The Station is a platform for all oceanographic disciplines with a scientific expertise widely based on a long tradition of interdisciplinary work, and a direct access to time series of physical, chemical and biological data registered with automated systems and variety of sensors deployed in the Bay of Calvi since 30 years. This platform provides the opportunity to reach coastal, pelagic, benthic, deep systems with a manageable cost and ship requirements in a pristine zone. [less ▲]

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See detailUse of multi-angle high-resolution imagery and 3D information for urban land-cover classification: a case study on Istanbul
Binard, Marc ULg; Tack, Frederik; Van de Voorde, Tim et al

in Joint SIG Workshop Urban - 3D - Radar - Thermal Remote Sensing and Developing Countries - Ghent, 22-24 September 2010 Book of Proceedings EUROPEAN ASSOCIATION OF REMOTE SENSING LABORATORIES (2010)

The BELSPO-MAMUD project focuses on the use of remote sensing data for measuring and modelling urban dynamics. Remote sensing is a wonderful tool to produce long time-series of sealed surface maps, which ... [more ▼]

The BELSPO-MAMUD project focuses on the use of remote sensing data for measuring and modelling urban dynamics. Remote sensing is a wonderful tool to produce long time-series of sealed surface maps, which are useful for this purpose. In the urban context of Istanbul, a very dynamic city, recent high resolution satellite images and medium resolution images from the past have been exploited to calibrate and validate a regression-based sub-pixel classification method allowing this production. Image classification in an urban context is a tricky task for several reasons: prominent occurrence of shadowed and occluded areas and urban canyons, spectral confusions between urban and non-urban materials at ground and roof levels, moderately hilly relief ... To cope with these difficulties the combined use of three types of data may be helpful: diachronic (vii), multi-angle and 3D data. A master multispectral and panchromatic QuickBird image and a panchromatic Ikonos stereopair, all acquired in March 2002, were used in combination with a multispectral and panchromatic Ikonos image of May 2005. A DSM was generated from the Ikonos stereopair and building vector file. It was used for orthorectification, building height estimation and classification. The area covered by the high resolution products was divided in 3 parts and each was classified independently. This application demonstrates that a recent high resolution land-cover classification produced using multi-date, multi-angle and DSM can be used to produce sealed surface maps from longer time-series of medium resolution images over large urban areas, thus enabling the analysis of urban dynamics. [less ▲]

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See detailUsing information on urban morphology derived from a time-series of medium resolution remote sensing data for the calibration of the moland urban growth model
van der Kwast; Van de Voorde, Tim; Binard, Marc ULg et al

in Joint SIG Workshop Urban - 3D - Radar - Thermal Remote Sensing and Developing Countries, Book of Proceedings EUROPEAN ASSOCIATION OF REMOTE SENSING LABORATORIES (2010)

Land-use change models are more and more used by planners and policy makers as tools to assess the impacts of their decisions on the spatial systems that they are to manage. To be usefully applicable the ... [more ▼]

Land-use change models are more and more used by planners and policy makers as tools to assess the impacts of their decisions on the spatial systems that they are to manage. To be usefully applicable the models need extensive calibration. Typically the required time series of land-use maps based on identical and consistent mapping methodologies, legends and scales are missing. As a result, the land-use changes measured in the time intervals studied are often the result of mismatches in the mapping procedures rather than real changes in the land-use patterns of interest. As an alternative, land-use products inferred from archived medium resolution remote sensing images have a large potential for usage in the historic calibration of land-use change models. However, inferring land-use classes from remote sensing data is not straightforward. Therefore, a calibration framework for land-use change modelling is being developed which is based on the comparison of spatial metrics derived from both remote sensing images and simulation results. Parameters used in the simulation model are tuned in such a way that the simulated patterns of urban growth, as described by the metrics, match the patterns observed in the remote sensing imagery. This study evaluates the applicability of spatial metrics calculated from urban masks derived from remote sensing images and simulated land-use maps for the historic calibration of the EU-MOLAND model of Dublin. Results show that the historic calibration can be improved by using remote sensing derived spatial metrics. [less ▲]

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See detailInferring urban morphology for the greater Dublin area from continuous sealed surface data: a metric based approach
Van de Voorde, Tim; Binard, Marc ULg; Cornet, Yves ULg et al

in Joint SIG Workshop Urban - 3D - Radar - Thermal Remote Sensing and Developing Countries Ghent, 22-24 September 2010 Book of Proceedings EUROPEAN ASSOCIATION OF REMOTE SENSING LABORATORIES (2010)

Urban land-use change models are valuable tools for assessing the spatial impact of alternative planning strategies via scenario analysis. A trustworthy output can only be obtained if the models are ... [more ▼]

Urban land-use change models are valuable tools for assessing the spatial impact of alternative planning strategies via scenario analysis. A trustworthy output can only be obtained if the models are correctly calibrated and validated, which requires historic land-use data. Land-use information is often inconsistent or unavailable at the desirable time interval. Earth observation satellites supply regular information on urban development and can provide additional data to improve calibration. To study urban growth patterns with a time-span that exceeds the availability of high resolution imagery, a mapping approach is required that succeeds in capturing structural information from medium resolution images. A rather novel approach in this research area is to describe urban structure by means of spatial metrics, which are usually applied on categorical data such as land-cover maps. The main objective of our research was to quantify the spatial structure of the Greater Dublin Area by applying metrics on continuous sealed surface data. Three types of urban metrics were derived at the level of spatial units (blocks): average building density, distribution characteristics of sub-pixel sealed surface fractions and spatial variability. Using these spatial metrics as quantitative variables describing urban structure, a supervised classification based on a multi-layer perceptron classifier was used to infer basic land-use categories. With this approach, we were able to distinguish broad land-use types such as residential areas and employment zones (e.g. industrial, commercial). This distinction is relevant for urban modelling as these classes represent important driving factors. Results of applying the proposed methodology on a timeseries of Landsat images are currently being used for improving the calibration of the MOLAND land-use model for Dublin. [less ▲]

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See detailQuantifying intra-urban morphology of the Greater Dublin area with spatial metrics derived from medium resolution remote sensing data
Van de Voorde, Tim; van der Kwast, Johannes; Engelen, Guy et al

in IEEE Proceedings of the 7th International Urban Remote Sensing Conference : Shanghai, May 20-22, 2009 (2009)

Spatial metrics derived from satellite imagery are useful measures to quantify structural characteristics of expanding cities, and can provide indications of functional land use types. Images of medium ... [more ▼]

Spatial metrics derived from satellite imagery are useful measures to quantify structural characteristics of expanding cities, and can provide indications of functional land use types. Images of medium resolution are cheap, widely available and are often part of extensive historic archives. Their lower resolution, on the other hand, inhibits studying urban morphology and change processes at a more detailed, intra-urban level. In this study, we develop spatial metrics for use on continuous sealed surface data produced by a sub-pixel classification of Landsat ETM+ imagery. The metrics characterise the shape of the cumulative frequency distribution of the estimated sub-pixel fractions within a building block by fitting an exponential and a sigmoid function with a least-squares approach. A classification tree is then used to relate the metric variables to urban land-use classes selected from the European MOLAND topology. This approach shows promising results, but still needs improvement which may be achieved by including spatially explicit metrics in the analysis. [less ▲]

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See detailCharacterising urban morphology with spectral unmixing and spatial metrics: a case study on Dublin
Canters, Frank; Van de Voorde, Tim; Binard, Marc ULg et al

in Proceedings of the 24th International Cartographic Conference (ICC 2009), (2009)

In today’s urbanising world, effective urban management and planning strategies are needed to temper the impact of urban change processes on the natural and human environment. To develop and monitor such ... [more ▼]

In today’s urbanising world, effective urban management and planning strategies are needed to temper the impact of urban change processes on the natural and human environment. To develop and monitor such strategies, and to assess their spatial impact, analysing changes in urban structure is essential. Data from earth observation satellites provide regular information on urban development and, as such, may contribute to the mapping and monitoring of cities and the modelling of urban dynamics. Especially images of medium resolution (Landsat, SPOT, …), which are cheap, widely available and often part of extensive historic archives, offer a wealth of information that may be useful for urban monitoring purposes. The lower resolution of this type of imagery, however, hampers the study of urban morphology and change processes at a more detailed, intra-urban level. Spectral unmixing approaches, which allow characterising land-cover distribution at sub-pixel level, may partly compensate for this lack of spatial detail, and may render medium-resolution imagery more useful for urban studies. The main research question addressed in this paper is how medium-resolution imagery could be used to describe urban morphology, by combining spectral unmixing approaches with spatial metrics. Spatial metrics derived from satellite imagery may be useful to quantify structural characteristics of expanding cities, and may provide indications of functional land use. In this study, we develop a set of urban metrics for use on continuous sealed surface data produced by sub-pixel classification of Landsat ETM+ imagery. Two sub-pixel classification approaches are examined for that purpose. In a first approach, we use a linear spectral mixture model with a vegetation and a non-vegetation endmember to deconvolve each pixel’s spectrum into fractional abundances of the two end member spectra, which are determined by visualising mixture space with principal component analysis. In a second approach, we use a linear regression model to estimate the proportion of vegetation cover within each Landsat pixel. In both approaches, an urban mask is used to indicate pixels belonging to urban land cover. Only pixels within the urban mask are subjected to sub-pixel classification. We hereby assume that the urban area does not contain bare soil and that the area of a pixel not covered by vegetation fully consists of sealed surface cover. The resulting sealed surface proportion map is then used to characterise urban morphology and land use by means of the shape of the cumulative frequency distribution of the estimated sealed surface fractions within a building block. A transformed logistic function is fitted to this distribution with a least-squares approach to obtain function parameters that are used as variables in a supervised classification approach, together with spatially explicit metrics (spatial variance and Moran’s I). Our study demonstrates that images from medium resolution sensors can be used to characterise intra-urban morphology, and that the structure of a building block as described by the proposed metrics gives an indication of its membership to certain morphological/functional urban classes. In future research we will incorporate socio-economic data in the metric analysis to further improve the distinction of urban land-use categories. The spatial metrics approach developed in this study will be used in experiments to improve the calibration of the MOLAND urban growth model, which is currently calibrated with historical land-use maps available for approximately 10-year intervals. [less ▲]

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See detailAtlas van België: Leeswijzer
Binard, Marc ULg; De Maeyer, Philippe; De Temmerman, Leen et al

Book published by Academia Press (2008)

Toute personne qui se déplace dans un environnement complexe souhaite pouvoir s'orienter et tente pour ainsi dire de «cartographier» l'espace dans lequel il évolue. Tant les personnes que les institutions ... [more ▼]

Toute personne qui se déplace dans un environnement complexe souhaite pouvoir s'orienter et tente pour ainsi dire de «cartographier» l'espace dans lequel il évolue. Tant les personnes que les institutions ont besoin d'une représentation compréhensible des environnements spatiaux dans lesquels elles vivent et se déplacent. Un troisième Atlas de Belgique est édité afin de répondre à cette nécessité, avec pour objectif d'ordonner l'abondance de données disponibles, principalement en les visualisant dans l'espace. L'actuelle société belge, avec sa complexité, ses fortes différenciations sociales et spatiales, ses anciennes oppositions et ses nouveaux fossés, est ainsi cartographiée. Le troisième 'Atlas de Belgique' tente de présenter les données d'un maximum de sources en faisant ressortir leur composante spatiale. [less ▲]

Detailed reference viewed: 42 (5 ULg)
See detailAtlas de Belgique - Guide de lecture
Binard, Marc ULg; De Maeyer, Philippe; De Temmerman, Leen et al

Book published by Academia Press (2008)

Toute personne qui se déplace dans un environnement complexe souhaite pouvoir s'orienter et tente pour ainsi dire de «cartographier» l'espace dans lequel il évolue. Tant les personnes que les institutions ... [more ▼]

Toute personne qui se déplace dans un environnement complexe souhaite pouvoir s'orienter et tente pour ainsi dire de «cartographier» l'espace dans lequel il évolue. Tant les personnes que les institutions ont besoin d'une représentation compréhensible des environnements spatiaux dans lesquels elles vivent et se déplacent. Un troisième Atlas de Belgique est édité afin de répondre à cette nécessité, avec pour objectif d'ordonner l'abondance de données disponibles, principalement en les visualisant dans l'espace. L'actuelle société belge, avec sa complexité, ses fortes différenciations sociales et spatiales, ses anciennes oppositions et ses nouveaux fossés, est ainsi cartographiée. Le troisième 'Atlas de Belgique' tente de présenter les données d'un maximum de sources en faisant ressortir leur composante spatiale. [less ▲]

Detailed reference viewed: 137 (29 ULg)
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See detailMeasuring and Modeling Urban Dynamics: Impact on Quality of Life and Hydrology. Objectives and methodology
Canters, Frank; Van de Voorde, Tim; Goossens, Rudi et al

(2007)

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See detailAccuracy assessment of an IKONOS derived DSM over urban and suburban area
Devriendt, Dennis; Goossens, Rudi; Binard, Marc ULg

(2007)

The availability of IKONOS stereo pairs has made it possible to generate Digital Surface Models of IKONOS data. Though it is possible to obtain a DSM from two images with a different viewing angle on the ... [more ▼]

The availability of IKONOS stereo pairs has made it possible to generate Digital Surface Models of IKONOS data. Though it is possible to obtain a DSM from two images with a different viewing angle on the same area, it is preferred to work with products ordered as stereo. Such stereo pairs have images that are made in the same orbital pass, resulting in a much better geometry of the stereo model. In this paper the accuracy of an IKONOS derived DSM of urban areas is assessed, based on DSMs from aerial photography and laser scanning. The quality and accuracy of a DSM derived from IKONOS stereo pairs has been assessed for test zones in two cities, Ghent and Liege. The test zones are characterized by a typical urban morphology (city center, residential, industry). The accuracy has been assessed for each of the different types of urban morphology in the study areas. An error surface is obtained by calculating the difference between the generated IKONOS surface models and reference surface models. This surface is used as a measure for the accuracy of the IKONOS surface model. Reference surface models from different origins are used (aerial photography, lidar, large scale 3D database). For the test zones in Liege, the relation between the DSM accuracy and different land cover types is studied in detail. Also the relation between DSM error and the topography will be investigated. [less ▲]

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See detailAnalysis of buildings height computed on a DSM generated from a VHR satellite stereopair
Binard, Marc ULg; Devriendt, D.; Cornet, Yves ULg et al

in Hostert, P.; Damm, A.; Schiefer, S. (Eds.) Proceedings of the First Workshop of the EARSeL Special Interest Group on Urban Remote Sensing "Challenges and Solutions" (2006)

At the final meeting of the SPIDER project, the users wanted to know if it was possible to evaluate the building height or the number of floors, from the DSM obtained from a VHR satellite stereopair ... [more ▼]

At the final meeting of the SPIDER project, the users wanted to know if it was possible to evaluate the building height or the number of floors, from the DSM obtained from a VHR satellite stereopair. Combined with the 2D delineation of the buildings – for example coming from the cadastre register - this information could be useful in urban studies – e.g. population density assessment - or to generate quasi realistic 3D views. In this example, the DSM is extracted from an IKONOS stereopair (DSMsat) on the hilly area of Liège in Belgium. It is used in combination with a 3D vector file. On the one hand, this file is used for the 2D delineation of the buildings. On the other hand, the third dimension provided by this file is also exploited for the assessment of the extracted building height. Moreover LIDAR data are also available over the test area, permitting the creation of a reference DSM (DSMref). * The first step of the process consists in the determination of the ground altitude around the buildings. A procedure was setup in order to compute it and to generate the DTM for the reference and satellite data (DTMref and DTMsat). * The second step consists in the extraction of statistics, for every building (min, max, mean, etc.) as well from the DSMsat and DSMref, as from the DTMsat and DTMref. The analysis shows that the satellite approach globally underestimates the building height of about 4 m. These results are discussed regarding building height versus the area and the heterogeneity of the roof height. [less ▲]

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See detailThe usefulness of VHR images for public administrations in an urban hilly region
Binard, Marc ULg; Cornet, Yves ULg; Donnay, Jean-Paul ULg

in Marçal, André (Ed.) "Global Developments in Environmental Earth Observation from Space" (2006)

This paper presents some results of the SPIDER project currently achieved in and around the city of Liège located in a hilly landscape. A Quick Bird image bundle product acquired on the 26th September ... [more ▼]

This paper presents some results of the SPIDER project currently achieved in and around the city of Liège located in a hilly landscape. A Quick Bird image bundle product acquired on the 26th September 2003 is used. Digital spatial data like Very High Resolution (VHR) satellite images could be provided to the public authorities of the Walloon region thanks to the Walloon cartographic gateway. In urban context and especially in hilly region, such images must be orthorectified using a Digital Surface Model (DSM). A 1 m resolution DSM was elaborated by exploiting all the 3D data available in the study area. Firstly, a TIN was generated from vector data (points, lines and polygons) selected, on the one hand, from the 1:50 000 (DTED-WGS) and the 1:10 000 (DTM- 10000, Top10v-GIS) cartographic database provided by the Belgian NGI and, on the other hand, from the 1:1 000 3D topographic database of the Walloon region (PICC). Then the TIN was rasterised and the DSM airborne LIDAR acquired along the main river-valleys is superimposed on the result. The ortho-image was then produced. The public authorities consider it as an end-product by itself which could be used in the place of the obsolete aerial orthophotos in the fast changing urban areas. Normally, the ortho-image of Liège should be available on the map server of the Walloon region in 2005, in order to check its usefulness for local and regional authorities. Moreover the local planning agency wish to take the opportunity of this study to update the spatial databases covering industrial and business development areas delineated on the urban plan. [less ▲]

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See detailUsage des données 3D IGN, PICC et SETHY pour l’orthorectification d’une image QuickBird en région liégeoise.
Binard, Marc ULg

in AM/FM-GIS BELUX News (2005), 32

This paper presents the first results of the SPIDER project obtained on a VHR satellite image (QuickBird) acquired on the Liège area (315 km²). It shows how a selection of data in the Walloon cartographic ... [more ▼]

This paper presents the first results of the SPIDER project obtained on a VHR satellite image (QuickBird) acquired on the Liège area (315 km²). It shows how a selection of data in the Walloon cartographic gateway allowed the making of a DSM needed at the orthorectification of the satellite image. [less ▲]

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See detailImproving spatial information extraction for local and regional authorities using Very-High-Resolution data - geometrical aspects
Devriendt, Dennis; Goossens, Rudi; Taillieu, Kristof et al

in Oluić, Marinko (Ed.) New Strategies for European Remote Sensing (2005)

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of ... [more ▼]

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of value-added products that fulfill some of the actual information needs, as expressed by Belgian authorities at the local and at the regional level. One of the technical research modules is focussing on the geometrical aspects of VHR data processing. The geometric precision of VHR data (QuickBird, IKONOS) is systematically evaluated, more specific for an urban and suburban environment using the GCP information obtained by GPS measurements. The 2D-georeferenced images is compared with ortho-rectified images in terms of their geometric accuracy. This will provide useful information about the limitations of 2Dcorrected data, and the necessity of acquiring ortho-rectified data, for different kinds of applications in each of the studied areas. The oblique viewing angle of images produced by VHR sensors like IKONOS and QuickBird has a strong influence on the geometrical displacement of objects, and on the occurrence of hidden areas in the image. The degree of displacement and the percentage of hidden areas are determined by the interaction between viewing angle, position of the sun, object height, and terrain characteristics (slope, aspect). In other words, the range of viewing angles that can be considered acceptable for purchasing an image of a certain area will depend on the morphological characteristics of the area. To study the interaction between all parameters involved, a theoretical model is implemented. First, the model is used to systematically study the impact of viewing angle on object displacement, shadow length and size of hidden areas in an image, by simultaneously varying the different morphological parameters. Next, the impact of viewing angle on the geometry of the image is simulated using the theoretical model and a DSM from aerial photography. The geometrical accuracy of a DSM from VHR data is compared with the accuracy of the DSM, derived from aerial photography at scales of 1:12000 and 1:4000). The satellite-derived DSM is used for ortho-rectification of VHR imagery. The accuracy of the ortho-rectified images is compared with ortho-rectifications of the same images, based on the aerial photo DSM. [less ▲]

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