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Ajouter le résultat dans votre panierDigital Elevation Model from the best results of different filtering of a LiDAR point cloud / T. Podobnikar in Transactions in GIS, vol 16 n° 5 (October 2012)
Titre : Digital Elevation Model from the best results of different filtering of a LiDAR point cloud Type de document : Article/Communication Auteurs : T. Podobnikar, Auteur ; Anja Vrecko, Auteur Année de publication : 2012 Article en page(s) : pp 603 - 617 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] filtrage de points
[Termes IGN] modèle numérique de surface
[Termes IGN] semis de pointsRésumé : (Auteur) The LiDAR point clouds captured with airborne laser scanning provide considerably more information about the terrain surface than most data sources in the past. This rich information is not simply accessed and convertible to a high quality digital elevation model (DEM) surface. The aim of the study is to generate a homogeneous and high quality DEM with the relevant resolution, as a 2.5D surface. The study is focused on extraction of terrain (bare earth) points from a point cloud, using a number of different filtering techniques accessible by selected freeware. The proposed methodology consists of: (1) assessing advantages/disadvantages of different filters across the study area, (2) regionalization of the area according to the most suitable filtering results, (3) data fusion considering differently filtered point clouds and regions, and (4) interpolation with a standard algorithm. The resulting DEM is interpolated from a point cloud fused from partial point clouds which were filtered with multiscale curvature classification (MCC), hierarchical robust interpolation (HRI), and the LAStools filtering. An important advantage of the proposed methodology is that the selected landscape and datasets properties have been more holistically studied, with applied expert knowledge and automated techniques. The resulting highly applicable DEM fulfils geometrical (numerical), geomorphological (shape), and semantic quality properties. Numéro de notice : A2012-513 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01332.x Date de publication en ligne : 10/10/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01332.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31959
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 603 - 617[article]
Titre : Hybrid of shape grammar and morphing for procedural modeling of 3D caves Type de document : Article/Communication Auteurs : T. Zawadzki, Auteur ; S. Nikiel, Auteur ; K. Warszawski, Auteur Année de publication : 2012 Article en page(s) : pp 619 - 633 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] données localisées 3D
[Termes IGN] grammaire de graphes
[Termes IGN] grotte
[Termes IGN] modélisation 3D
[Termes IGN] morphageRésumé : (Auteur) Procedural modeling of three-dimensional shapes plays a significant role in many areas nowadays. Methods based on the automation of the modeling process offer a variety of three-dimensional structures, saving time and money. Geometry synthesis is currently used in many fields including digital cinema, electronic entertainment and simulation. There is a need to replace designers' work with intelligent automated algorithms, especially in the case of terrain modeling. This article addresses the problem of modeling virtual caves and tunnels and presents alternative solutions in the form of a hybrid system. The innovative approach combines two independent methods well known in computer graphics: shape grammars and shape morphing for modeling three-dimensional geometry. In the modeling process, it is possible to obtain the characteristics of 3D structures with non-spherical mesh topology. The objects and their transformations are described by functions, while production grammars define the geometry modeling process. The scene graph can be expanded by classic productions and optimized by morphing productions. Obtained shapes can be freely deformed in subsequent productions. The system offers control over the process of modeling and the resulting structure can be rendered up to a high level of realism. We also propose some measures that can be used to verify the modeling results: coefficients indicating the degree of convexity of three-dimensional model topology based on the structure of inequality, the volume of the model, surface model and the number of model elements. Numéro de notice : A2012-514 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01322.x Date de publication en ligne : 15/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01322.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31960
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 619 - 633[article]
Titre : High resolution DEM generation in high-alpine terrain using airborne remote sensing techniques Type de document : Article/Communication Auteurs : Y. Bühler, Auteur ; M. Marty, Auteur ; C. Ginzler, Auteur Année de publication : 2012 Article en page(s) : pp 635 - 647 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] Alpes centrales
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] modèle numérique de surface
[Termes IGN] SuisseRésumé : (Auteur) Up-to-date and accurate digital elevation models (DEMs) are essential for many applications such as numerical modeling of mass movements or mapping of terrain changes. Today the Federal Department of Topography, swisstopo, provides Digital Terrain Models (DTMs) and Digital Surface Models (DSMs) derived from airborne LiDAR data with a high spatial resolution of 2 m covering the entire area of Switzerland below an elevation of 2000 m a.s.l.. However, above an elevation of 2000 m a.s.l., which is typical for high-alpine terrain, the best product available is the a DTM with a spatial resolution of 25 m. This spatial resolution is insufficient for many applications in complex terrain. In this study, we investigate the quality of DSMs derived from opto-electronic scanner data (ADS80; acquired in autumn 2010) using photogrammetric image correlation techniques based on the multispectral nadir and backward looking sensor data. As reference, we take a high precision airborne LiDAR data set with a spatial resolution of ca. 0.5 m, acquired in late summer 2010, covering the Grabengufer/Dorfbach catchment near Randa, VS. We find the deviations between the two datasets are surprisingly low. In terrain with inclination angles of less than 30° the RMSE is below 0.5 m. In extremely steep terrain of more than 50° the RMSE goes up to 2 m and outliers increase significantly. We also find dependencies of the deviations on illumination conditions and ground cover classes. Finally we discuss advantages and disadvantages of the different data acquisition methods. Numéro de notice : A2012-515 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01331.x Date de publication en ligne : 20/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01331.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31961
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 635 - 647[article]
Titre : Slope analysis of fuzzy surfaces Type de document : Article/Communication Auteurs : J. Caha, Auteur ; P. Tucek, Auteur ; Alena Vondrakova, Auteur ; L. Paclikova, Auteur Année de publication : 2012 Article en page(s) : pp 649 - 661 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] incertitude géométrique
[Termes IGN] logique floue
[Termes IGN] penteRésumé : (Auteur) Analysis of the slope is one of the fundamental analyses within geoinformatics, especially its initial calculation. Slope analysis is usually used as the first step in much more sophisticated analyses as well as in complex models of natural phenomena. Fuzzy surfaces provide representation of geographical phenomena with all aspects of the uncertainty (i.e. both in terms of the description of reality or the uncertainty of measurement). The uncertainty in the input surface is crucial for analysis of slope. A high level of uncertainty can significantly affect the result of slope analysis. The Neighbourhood method was utilized for calculating with fuzzy numbers and to perform slope analysis of the fuzzy surface. The main reason for choosing this method is that it belongs to the most common tools in GIS software (e.g. both ArcGIS and GRASS). The computation with fuzzy numbers instead of crisp numbers allows evaluation of uncertainty of the resultant slope. The aim of this article is to present the process of slope calculation with fuzzy numbers as well as all necessary algorithms that are needed for such calculation. The further analysis of uncertainty provides important information for the process of decision making. The level of uncertainty in the results of the above-mentioned analysis can be as important as the actual result. It is especially important in situations where the amount of uncertainty varies at higher values. Numéro de notice : A2012-516 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01333.x Date de publication en ligne : 10/10/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01333.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31962
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 649 - 661[article]
Titre : Georelief transfiguration in areas affected by open-cast mining Type de document : Article/Communication Auteurs : J. Pacina, Auteur ; K. Novak, Auteur ; J. Popelka, Auteur Année de publication : 2012 Article en page(s) : pp 663 - 679 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] analyse diachronique
[Termes IGN] Bohème
[Termes IGN] carte ancienne
[Termes IGN] mine
[Termes IGN] modèle numérique de surface
[Termes IGN] photographie aérienne
[Termes IGN] République TchèqueRésumé : (Auteur) Open-cast mining activity causes the largest georelief transfigurations all over the world. Large localities in north-west Bohemia (the Czech Republic) are affected. In this area, we focus on a very significant case: the royal town Most, which has been turned into a lake. The main aim of this article is the reconstruction of the original georelief in different time periods together with analysis showing the process of landscape devastation. The workflow and analysis is based on precise elevation data obtained from aerial photographs and old maps. The georelief development is reconstructed using the digitized contour lines contained in Derived state-map 1:5,000 (SMO5) from the years 1953, 1972, and 1980; maps of the 3rd Military Survey (year 1936); and digital surface models (DSM) extracted, using the pixel correlation method, from aerial images (year 1953 and 2008). The most important results of the analysis are digital terrain models showing the evolution of the landscape which may be used for many purposes in landscape development analysis, historical applications, visualization or landscape reclamation. Numéro de notice : A2012-517 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01339.x Date de publication en ligne : 22/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01339.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31963
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 663 - 679[article]
Titre : A new 3-D solar radiation model for 3-D city models Type de document : Article/Communication Auteurs : Jaroslav Hofierka, Auteur ; M. Zlocha, Auteur Année de publication : 2012 Article en page(s) : pp 681 - 690 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] arc
[Termes IGN] ensoleillement
[Termes IGN] GRASS
[Termes IGN] milieu urbain
[Termes IGN] modèle 3D de l'espace urbain
[Termes IGN] modèle de transfert radiatif
[Termes IGN] ombre
[Termes IGN] rayonnement solaire
[Termes IGN] voxelRésumé : (Auteur) Estimates of solar radiation distribution in urban areas are often limited by the complexity of urban environments. These limitations arise from spatial structures such as buildings and trees that affect spatial and temporal distributions of solar fluxes over urban surfaces. The traditional solar radiation models implemented in GIS can address this problem only partially. They can be adequately used only for 2-D surfaces such as terrain and rooftops. However, vertical surfaces, such as facades, require a 3-D approach. This study presents a new 3-D solar radiation model for urban areas represented by 3-D city models. The v.sun module implemented in GRASS GIS is based on the existing solar radiation methodology used in the topographic r.sun model with a new capability to process 3-D vector data representing complex urban environments. The calculation procedure is based on the combined vector-voxel approach segmenting the 3-D vector objects to smaller polygon elements according to a voxel data structure of the volume region. The shadowing effects of surrounding objects are considered using a unique shadowing algorithm. The proposed model has been applied to the sample urban area with results showing strong spatial and temporal variations of solar radiation flows over complex urban surfaces. Numéro de notice : A2012-518 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01337.x Date de publication en ligne : 22/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01337.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31964
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 681 - 690[article]
Titre : Digital terrain model resolution and its influence on estimating the extent of rockfall areas Type de document : Article/Communication Auteurs : T. Zieher, Auteur ; T. Formanek, Auteur ; Magnus Bremer, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 691 - 699 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] éboulement
[Termes IGN] modèle numérique de terrain
[Termes IGN] Python (langage de programmation)Résumé : (Auteur) As rockfall can cause a great deal of damage, it is essential to know its spatial propagation. Rockfall models are sensitive to the resolution of input data, i.e. the Digital Terrain Model (DTM) used. Nowadays, high resolution elevation data are available area-wide from airborne laser scanning (ALS). However, rockfall models are designed for analysis on a certain scale, which means that high resolution input might not necessarily improve model results (e.g. for regional scale studies). Our aim is to estimate the reach of rockfall by analysing different input resolutions of an ALS DTM. The presented empirically–based model, implemented in Python 2.7, is a modified version of the zenital method including an iterative random walk trajectory model, which is designed for rockfall hazard assessment at the regional scale. Trajectories and rockfall probability maps are generated for selected DTM input resolutions. The comparison shows that high resolution DTMs do consider local topography better and thus lead to more realistic results than low resolution DTMs. Numéro de notice : A2012-519 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01334.x Date de publication en ligne : 20/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01334.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31965
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 691 - 699[article]
Titre : Modelling flow routing in permafrost landscapes with TWI: an evaluation against site-specific wetness measurements Type de document : Article/Communication Auteurs : A. Persson, Auteur ; A. Hasan, Auteur ; J. Tang, Auteur ; Petter Pilesjö, Auteur Année de publication : 2012 Article en page(s) : pp 701 - 713 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] changement climatique
[Termes IGN] dégel
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] humidité du sol
[Termes IGN] modèle numérique de surface
[Termes IGN] pergélisol
[Termes IGN] Suède
[Termes IGN] tourbeRésumé : (Auteur) In northern peatlands the thawing of permafrost increasing the active layer depth and changing the hydrology may lead to feedbacks in the climate system through changes in the biogeochemistry of carbon. We are examining this association on the Stordalen peatland complex in subarctic Sweden by analyzing a DEM derived from LiDAR-data and the calculated TWI [Topographical Wetness Index]. The DEM, with a spatial resolution of 1 m, and the TWI are evaluated against two seasons of water level measurements from 30 sites in the peatland. The TWI is calculated with a form-based flow routing algorithm which produces a natural flow routing pattern. In permafrost wetlands the topography is the major driver and is very important even though its magnitude is low. Site-specific wetness (SSW) measurements from the sites were compared with the different peatland types that occur in the study area, i.e. fen, internal fen and palsa. The results showed a strong correlation between the TWI and the palsa. The TWI was better at describing general patterns than site-specific hydrology. The evaluation of spatial patterns of TWI against SSW reveal the resolution required to develop the technique to be useful for climate change studies. Numéro de notice : A2012-520 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01338.x Date de publication en ligne : 22/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01338.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31966
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 701 - 713[article]
Titre : Using thermal remote sensing in environmental studies Type de document : Article/Communication Auteurs : M. Kubiak, Auteur ; P. Dzieszko, Auteur Année de publication : 2012 Article en page(s) : pp 715 - 732 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] bilan thermique
[Termes IGN] distribution spatiale
[Termes IGN] ensoleillement
[Termes IGN] occupation du sol
[Termes IGN] Pologne
[Termes IGN] relief
[Termes IGN] température au sol
[Termes IGN] variabilitéRésumé : (Auteur) Thermovision is a relatively new method of remote sensing with applications in areas such as military operations, residential monitoring, technological process control and emergency management. Surprisingly, it has not seen much application in environmental studies. The article presents a method of using thermovision for topoclimatic studies. The method is based on the spatial distribution of land surface temperature (LST). The LST distribution indicates the amount of solar energy reaching the Earth surface and depends primarily on terrain shape and land cover types. By analyzing the LST distribution, one can determine spatial topoclimatic variability. The LST derived topoclimatic classification was compared with the theoretical topoclimatic classification based on heat balance. New classes of topoclimates were created and some of the existing types were diversified into more detailed subtypes. The analysis of selected lowland areas in north-western Poland revealed that both land cover and terrain shape characteristics had a significant impact on the LST distribution, contrary to the expectation of land cover characteristics being more important than terrain shape. The article demonstrates the possibilities of using thermovision in environmental research and presents a new method of topoclimate delimitation based on thermal remote sensing data and geographical information systems (GIS) techniques comparing. The LST classification method with conventional methods based on DEM and land cover analysis. Numéro de notice : A2012-521 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01336.x Date de publication en ligne : 15/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01336.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31967
in Transactions in GIS > vol 16 n° 5 (October 2012) . - pp 715 - 732[article]
