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Cartographic symbol design considerations for the space–time cube / Christopher League in Cartographic journal (the), Vol 56 n° 2 (May 2019)  

Public [article]  inCartographic journal (the) > Vol 56 n° 2 (May 2019) . - pp 117 - 133 Titre : Cartographic symbol design considerations for the space–time cube Type de document : Article/Communication Auteurs : Christopher League, Auteur ; Patrick Kennelly, Auteur Année de publication : 2019 Article en page(s) : pp 117 - 133 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] conception cartographique [Termes descripteurs IGN] cube espace-temps [Termes descripteurs IGN] données localisées 2D [Termes descripteurs IGN] données spatiotemporelles [Termes descripteurs IGN] figuré ponctuel [Termes descripteurs IGN] saturation de la couleur [Termes descripteurs IGN] sémiologie graphique [Termes descripteurs IGN] symbole graphique 3D [Vedettes matières IGN] Géovisualisation Résumé : (Auteur) The cartographic representation of geographic phenomena in the space–time cube comes with special challenges and opportunities when compared with two-dimensional maps. While the added dimension allows the display of attributes that vary with time, it is difficult to display rapidly varying temporal data given the limited display height. In this study, we adapt 2D cyclic point symbols to construct 3D surfaces designed along a helical path for the space–time cube. We demonstrate how these complex 3D helical surfaces can display detailed data, including data reported daily over 100 years and data reported in four-hour intervals over a year. To create the point symbols, each value is plotted along the curve of a helix, with each turn of the helix representing one year or week, respectively. The model is modified by varying the radii from the time axis to all points using the attribute value, in these cases maximum daily temperature and four-hourly ridership, and then creating a triangulated surface from the resulting points. Using techniques common to terrain representation, we apply hue and saturation to the surface based on attribute values, and lightness based on relief shading. Multiple surfaces can be displayed in a space–time cube with a consistent time interval facing the viewer, and the surfaces or viewer perspective can be rotated to display synchronized variations. We see this method as one example of how cartographic design can refine or enhance operations in the space–time cube. Numéro de notice : A2019-239 Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2018.1533291 date de publication en ligne : 29/05/2019 En ligne : https://doi.org/10.1080/00087041.2018.1533291 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92931 [article]

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Smart cartographic background symbolization for map mashups in geoportals : A proof of concept by example of landuse representation / Nadia H. Panchaud in Cartographic journal (the), Vol 56 n° 1 (February 2019)  

Public [article]  inCartographic journal (the) > Vol 56 n° 1 (February 2019) . - pp 42 - 58 Titre : Smart cartographic background symbolization for map mashups in geoportals : A proof of concept by example of landuse representation Type de document : Article/Communication Auteurs : Nadia H. Panchaud, Auteur ; Lorenz Hurni, Auteur Année de publication : 2019 Article en page(s) : pp 42 - 58 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes descripteurs IGN] application composite [Termes descripteurs IGN] cartographie par internet [Termes descripteurs IGN] conception cartographique [Termes descripteurs IGN] geoportail [Termes descripteurs IGN] niveau de gris (image) [Termes descripteurs IGN] saturation de la couleur [Termes descripteurs IGN] sémiologie graphique Résumé : (Auteur) Geospatial data are now widely available to the general public thanks to geoportals and online mapping platforms. However, creating a map involves more than just combining data layers. Thus we develop cartographic functions for geoportals to support better visual hierarchy in user map mashups. This includes a couple of preparatory steps followed by a smart cartographic background symbolization derived from the original layer style. We evaluate different approaches to background symbolization: greyscale, desaturation, and smart background. The different background symbolization methods are analysed with two concrete map examples and evaluated with a survey. The smart background symbolization developed in this work improves the visual hierarchy of the map mashup by reducing the visual importance of the background layers. Numéro de notice : A2019-447 Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2017.1414019 date de publication en ligne : 16/11/2018 En ligne : https://doi.org/10.1080/00087041.2017.1414019 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92793 [article]

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The effect of spatial distance on the discriminability of colors in maps / Alžběta Brychtová in Cartography and Geographic Information Science, Vol 44 n° 3 (May 2017)  

Public [article]  inCartography and Geographic Information Science > Vol 44 n° 3 (May 2017) . - pp 229 - 245 Titre : The effect of spatial distance on the discriminability of colors in maps Type de document : Article/Communication Auteurs : Alžběta Brychtová, Auteur ; Arzu Çöltekin, Auteur Année de publication : 2017 Article en page(s) : pp 229 - 245 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Rédaction cartographique [Termes descripteurs IGN] couleur (rédaction cartographique) [Termes descripteurs IGN] lecture de carte [Termes descripteurs IGN] lisibilité perceptive [Termes descripteurs IGN] symbole graphique [Termes descripteurs IGN] teinte Résumé : (auteur) The spatial distance (gap) between map symbols can have a great impact on their discriminability, however, there is little empirical evidence to establish spatial and attribute thresholds. In this paper, we examine the effect of the spatial gap in discriminability of color hue and value, that is, we conducted an online study to obtain performance metrics; then an eye-tracking study to understand participants’ strategies and cognitive processes. Participants completed two experimental tasks (compare two areas and decide if their color is the same; and compare three areas and rank them from the lightest to the darkest). The color distances and the spatial distances were strictly controlled for the compared areas. Our analyses confirmed that, overall, increasing the gap between colors has a consistent negative impact on the ability to differentiate them with both sequential and qualitative schemes. Furthermore, we observed that sequential schemes require larger color distances than qualitative schemes for discriminability. Finally, our results suggested that for qualitative colors, the largest tested color distance ∆E00 = 10 yields considerably higher levels of accuracy in color discrimination (even when the spatial gap between the two colors is large), thus we recommend ∆E00 = 10 to practicing cartographers and other information visualization designers. Numéro de notice : A2017-209 Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/15230406.2016.1140074 En ligne : http://dx.doi.org/10.1080/15230406.2016.1140074 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85046 [article]

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Efficient terrestrial laser scan segmentation exploiting data structure / Hamid Mahmoudabadi in ISPRS Journal of photogrammetry and remote sensing, vol 119 (September 2016)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 119 (September 2016) . - pp 135 - 150 Titre : Efficient terrestrial laser scan segmentation exploiting data structure Type de document : Article/Communication Auteurs : Hamid Mahmoudabadi, Auteur ; Michael J. Olsen, Auteur ; Sinisa Todorovic, Auteur Année de publication : 2016 Article en page(s) : pp 135 - 150 Note générale : Bibliogaphie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes descripteurs IGN] colorimétrie [Termes descripteurs IGN] densité d'information [Termes descripteurs IGN] intensité lumineuse [Termes descripteurs IGN] modèle logique de données [Termes descripteurs IGN] plus proche voisin (algorithme) [Termes descripteurs IGN] segmentation [Termes descripteurs IGN] semis de points [Termes descripteurs IGN] système de coordonnées [Termes descripteurs IGN] télémétrie laser terrestre Résumé : (Auteur) New technologies such as lidar enable the rapid collection of massive datasets to model a 3D scene as a point cloud. However, while hardware technology continues to advance, processing 3D point clouds into informative models remains complex and time consuming. A common approach to increase processing efficiently is to segment the point cloud into smaller sections. This paper proposes a novel approach for point cloud segmentation using computer vision algorithms to analyze panoramic representations of individual laser scans. These panoramas can be quickly created using an inherent neighborhood structure that is established during the scanning process, which scans at fixed angular increments in a cylindrical or spherical coordinate system. In the proposed approach, a selected image segmentation algorithm is applied on several input layers exploiting this angular structure including laser intensity, range, normal vectors, and color information. These segments are then mapped back to the 3D point cloud so that modeling can be completed more efficiently. This approach does not depend on pre-defined mathematical models and consequently setting parameters for them. Unlike common geometrical point cloud segmentation methods, the proposed method employs the colorimetric and intensity data as another source of information. The proposed algorithm is demonstrated on several datasets encompassing variety of scenes and objects. Results show a very high perceptual (visual) level of segmentation and thereby the feasibility of the proposed algorithm. The proposed method is also more efficient compared to Random Sample Consensus (RANSAC), which is a common approach for point cloud segmentation. Numéro de notice : A2016-781 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://dx.doi.org/10.1016/j.isprsjprs.2016.05.015 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82477 [article]

Assessing the effectiveness and efficiency of map colour for colour impairments using an eye-tracking approach / Weihua Dong in Cartographic journal (the), Vol 53 n° 2 (May 2016)  

Public [article]  inCartographic journal (the) > Vol 53 n° 2 (May 2016) . - pp 166 - 176 Titre : Assessing the effectiveness and efficiency of map colour for colour impairments using an eye-tracking approach Type de document : Article/Communication Auteurs : Weihua Dong, Auteur ; S. Zhang, Auteur ; Hua Liao, Auteur Année de publication : 2016 Article en page(s) : pp 166 - 176 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Rédaction cartographique [Termes descripteurs IGN] Chine [Termes descripteurs IGN] couleur (rédaction cartographique) [Termes descripteurs IGN] daltonisme [Termes descripteurs IGN] lecture de carte [Termes descripteurs IGN] oculométrie [Termes descripteurs IGN] teinte Résumé : (Auteur) Colour impairments influences access to geographical information which is usually represented by colour maps. Three dimensions of colour: Hue, Saturation and Value (HSV), are intuitive and most critical visual variables in map design. In this paper, we specifically focus on colour deficiency of red-green colour impairments. A controlled experiment was designed and conducted to explore how three colour dimensions (HSV) affect the abilities of people with normal colour vision or with red-green colour impairments to distinguish colours in maps. An eye-tracking approach was applied to quantify the accuracy and response time by capturing user eye movements to analyse the effectiveness and efficiency. In this study, we used one section of the administrative map of Hebei Province to test participant responses to area features. Differences of effectiveness and efficiency across normal colour vision and red-green colour impairments were compared. Multiple comparisons among Hue, Saturation and Value were analysed. Results show that for both normal colour vision and red-green colour impairments, Hue is the most differentiable than Saturation and Value. Saturation and Value are at the same level to be differentiated and more difficult to be distinguished. Guidelines of designing maps for both normal colour vision and red-green colour impairments were derived. The results of this study can be helpful to improve the map designs for colour deficiency. Numéro de notice : A2016-512 Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://dx.doi.org/10.1179/1743277413Y.0000000053 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81583 [article]

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An unsupervised urban change detection procedure by using luminance and saturation for multispectral remotely sensed images / Su Ye in Photogrammetric Engineering & Remote Sensing, PERS, vol 81 n° 8 (August 2015)

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Segmentation d'images aériennes par coopération LPE-régions et LPE-contours, application à la caractérisation de toitures / Youssef El Merabet in Revue Française de Photogrammétrie et de Télédétection, n° 206 (Avril 2014)

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A large format camera for national mapping purposes / Jean Philippe Souchon in Revue Française de Photogrammétrie et de Télédétection, n° 200 (Novembre 2012)

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Représentation des couleurs d'une carte pour l'analyse : proportions, relations, harmonie ? / Laurent Jégou in Cartes & Géomatique, n° 213 (septembre 2012)  

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Automatic symbolisation methods for geoportals / Ara Toomanian in Cartographic journal (the), vol 49 n° 2 (May 2012)

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Imagerie numérique / Christine Fernandez-Maloigne (2012)

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Traitements numériques des images de télédétection, Vol. 1. Notions de base sur les couleurs / Olivier de Joinville (2012)

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Hierarchical segmentation-based software for cover classification analyses of seabed images (Seascape) / Nuria Teixido in Marine Ecology Progress Series (MEPS), n° 431 ([09/06/2011])    

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Colorisation et texturation temps réel d'environnements urbains par système mobile avec scanner laser et caméra fish-eye / Jean-Emmanuel Deschaud in Revue Française de Photogrammétrie et de Télédétection, n° 192 (Septembre 2010)

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Influence of image characteristics on image quality / T. Royer (2010)

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